Science.gov

Sample records for gaseous emissions characteristics

  1. Gaseous Emissions from Wastewater Facilities.

    PubMed

    Koh, Sock-Hoon; Shaw, Andrew R

    2016-10-01

    A review of the literature published in 2015 on topics relating to gaseous emissions from wastewater facilities is presented. This review is divided into the following sections: odorant emissions from wastewater treatment plants (WWTPs); greenhouse gas (GHG) emissions from WWTPs; gaseous emissions from wastewater collection systems; physiochemical odor/emissions control methods; biological odor/emissions control methods; odor characterization/monitoring; and odor impacts/ risk assessments. PMID:27620089

  2. Emission characteristics and air-surface exchange of gaseous mercury at the largest active landfill in Asia

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Li, Zhonggen; Chai, Xiaoli; Hao, Yongxia; Lin, Che-Jen; Sommar, Jonas; Feng, Xinbin

    2013-11-01

    The emission characteristics and air-surface exchange of gaseous elemental mercury (GEM) at Laogang landfill in Shanghai, China, the largest active landfill in Asia, has been investigated during two intensive field campaigns in 2011 and 2012. The mercury (Hg) content in municipal solid waste (MSW) varied widely from 0.19 to 1.68 mg kg-1. Over the closed cell in the landfill, the mean ambient air GEM concentration was virtually indistinguishable from the hemispherical background level (1.5-2.0 ng m-3) while the concentration downwind of ongoing landfill operation (e.g. dumping, burying and compacting of MSW) was clearly elevated. GEM emission through landfill gas (LFG) was identified as a significant source. GEM concentrations in LFGs collected from venting pipes installed in different landfill cells varied widely from 3.0 to 1127.8 ng m-3. The GEM concentrations were found negatively correlated to the age of LFG cells, suggesting GEM released through LFG declined readily with time. The GEM emission from this source alone was estimated to be 1.23-1.73 mg h-1. GEM emission from cover soil surfaces was considerably lower and at a scale comparable to that of background soil surfaces. This is in contrast to earlier reports showing enhanced GEM emissions from landfill surfaces in Southern China, probably due to the difference in soil Hg content and gas permeability characteristics of soils at different sites. Vertical concentration profiles of GEM in the interstitial gas of buried MSW were sampled, perhaps for the first time, which exhibited a wide spatial variability (4.9-713.1 ng m-3) in the 3-year-old landfill cell investigated. GEM emission from landfill operation was estimated to be 290-525 mg h-1 using a box model. This suggests that GEM degassing from Laogang landfill is quantitatively largely dominated by emissions from daily landfilling operations with a much smaller contribution from LFG venting and insignificant (bi-directional fluxes near zero) contribution

  3. Characteristics of Gaseous Carbon Emission from a Tropical Peatland Fire: A Plot-Scale Field Experiment in Central Kalimantan, Indonesia

    NASA Astrophysics Data System (ADS)

    Hamada, Y.; Darung, U.; Limin, S. H.; Hatano, R.

    2014-12-01

    Tropical peatland in Southeast Asia is a vast reservoir of terrestrial carbon, which covers 24.8 million hectares and stores 68.5 PgC peat, equal to 11-14% of global peat carbon. In recent decades, large scale peatland fire has occurred frequently in that region, in which many areas of peatland were reclaimed with intention to use the land for forest plantation and rice paddy. We conducted a plot-scale peat burning experiment to elucidate the characteristics of gaseous carbon emission from a tropical peatland fire at the ground level. The experimental site was established at an open area 20 km southeast from Palangka Raya, Central Kalimantan Province, Indonesia. The size of the burning plot is 4 m in length and 3 m in width. Gas samples were collected at heights of 1.0, 0.5, 0.0 (aboveground), -0.1 and -0.2 m (belowground) through stainless steel and/or aluminum tubes settled across the edge of the plot. The concentrations of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and particulate matter (PM) was determined. Soil temperature was recorded every 10 minutes 0.1 and 0.2 m below the ground surface. Twelve iron rods were installed in 1-m by 1-m square grid to determine the depth of burn scar. After ignition, flaming stage of peat burning was ceased within 1-2 hours. The following smoldering stage continued for a week. In the flaming stage, soil temperature at -0.1 m increased tentatively. After the smoldering stage began, the temperature rapidly increased to 350-450°C. Response of soil temperature at -0.2 m was less prominent. Concentrations of gaseous components became maximal in the flaming stage. During the smoldering stage, the concentrations gradually decreased. The influence of burning on CO2 and PM was prominently remained at -0.1 m, whereas those at -0.2 m were not so much. The averaged burnt depth was 5.8±5.1 cm. Based on bulk density of 0.22 g/cm3 and carbon content of 55.5%, the amount of carbon lost from the plot was 85.3 kg. Most of the

  4. Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 1: gaseous and particulate matter emissions.

    PubMed

    Lobo, Prem; Rye, Lucas; Williams, Paul I; Christie, Simon; Uryga-Bugajska, Ilona; Wilson, Christopher W; Hagen, Donald E; Whitefield, Philip D; Blakey, Simon; Coe, Hugh; Raper, David; Pourkashanian, Mohamed

    2012-10-01

    Growing concern over emissions from increased airport operations has resulted in a need to assess the impact of aviation related activities on local air quality in and around airports, and to develop strategies to mitigate these effects. One such strategy being investigated is the use of alternative fuels in aircraft engines and auxiliary power units (APUs) as a means to diversify fuel supplies and reduce emissions. This paper summarizes the results of a study to characterize the emissions of an APU, a small gas turbine engine, burning conventional Jet A-1, a fully synthetic jet fuel, and other alternative fuels with varying compositions. Gas phase emissions were measured at the engine exit plane while PM emissions were recorded at the exit plane as well as 10 m downstream of the engine. Five percent reduction in NO(x) emissions and 5-10% reduction in CO emissions were observed for the alternative fuels. Significant reductions in PM emissions at the engine exit plane were achieved with the alternative fuels. However, as the exhaust plume expanded and cooled, organic species were found to condense on the PM. This increase in organic PM elevated the PM mass but had little impact on PM number. PMID:22913288

  5. Gaseous emissions from waste combustion.

    PubMed

    Werther, Joachim

    2007-06-18

    An overview is given on methods and technologies for limiting the gaseous emissions from waste combustion. With the guideline 2000/76/EC recent European legislation has set stringent limits not only for the mono-combustion of waste in specialized incineration plants but also for co-combustion in coal-fired power plants. With increased awareness of environmental issues and stepwise decrease of emission limits and inclusion of more and more substances into the network of regulations a multitude of emission abatement methods and technologies have been developed over the last decades. The result is the state-of-the-art waste incinerator with a number of specialized process steps for the individual components in the flue gas. The present work highlights some new developments which can be summarized under the common goal of reducing the costs of flue gas treatment by applying systems which combine the treatment of several noxious substances in one reactor or by taking new, simpler routes instead of the previously used complicated ones or - in the case of flue gas desulphurisation - by reducing the amount of limestone consumption. Cost reduction is also the driving force for new processes of conditioning of nonhomogenous waste before combustion. Pyrolysis or gasification is used for chemical conditioning whereas physical conditioning means comminution, classification and sorting processes. Conditioning yields a fuel which can be used in power plants either as a co-fuel or a mono-fuel and which will burn there under much better controlled conditions and therefore with less emissions than the nonhomogeneous waste in a conventional waste incinerator. Also for cost reasons, co-combustion of wastes in coal-fired power stations is strongly pressing into the market. Recent investigations reveal that the co-firing of waste can also have beneficial effects on the operating behavior of the boiler and on the gaseous emissions. PMID:17339077

  6. 40 CFR 87.71 - Compliance with gaseous emission standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES Test Procedures for Engine Exhaust Gaseous Emissions (Aircraft and Aircraft Gas Turbine Engines) § 87.71 Compliance with gaseous emission standards. Compliance with each gaseous emission standard by an aircraft engine shall...

  7. 40 CFR 87.71 - Compliance with gaseous emission standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES Test Procedures for Engine Exhaust Gaseous Emissions (Aircraft and Aircraft Gas Turbine Engines) § 87.71 Compliance with gaseous emission standards. Compliance with each gaseous emission standard by an aircraft engine shall...

  8. 40 CFR 90.418 - Data evaluation for gaseous emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Data evaluation for gaseous emissions. 90.418 Section 90.418 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.418...

  9. 40 CFR 91.418 - Data evaluation for gaseous emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Data evaluation for gaseous emissions. 91.418 Section 91.418 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust...

  10. ENVIRONMENTAL ASSESSMENT DATA SYSTEMS, USER GUIDE, GASEOUS EMISSIONS DATA SYSTEM

    EPA Science Inventory

    The report is a user guide to the Gaseous Emissions Data System (GEDS), a computerized data base on gaseous emissions from stationary point sources. GEDS is one of four waste stream data bases which are components of the Environmental Assessment Data Systems (EADS). The EADS conc...

  11. Gaseous emissions from plants in controlled environments

    NASA Technical Reports Server (NTRS)

    Dubay, Denis T.

    1988-01-01

    Plant growth in a controlled ecological life support system may entail the build-up over extended time periods of phytotoxic concentrations of volatile organic compounds produced by the plants themselves. Ethylene is a prominent gaseous emission of plants, and is the focus of this report. The objective was to determine the rate of ethylene release by spring wheat, white potato, and lettuce during early, middle, and late growth stages, and during both the light and dark segments of the diurnal cycle. Plants grown hydroponically using the nutrient film technique were covered with plexiglass containers for 4 to 6 h. At intervals after enclosure, gas samples were withdrawn with a syringe and analyzed for ethylene with a gas chromatograph. Lettuce produced 10 to 100 times more ethylene than wheat or potato, with production rates ranging from 141 to 158 ng g-dry/wt/h. Wheat produced from 1.7 to 14.3 ng g-dry/wt/h, with senescent wheat producing the least amount and flowering wheat the most. Potatoes produced the least amount of ethylene, with values never exceeding 5 ng g-dry/wt/h. Lettuce and potatoes each produced ethylene at similar rates whether in dark period or light period. Ethylene sequestering of 33 to 43 percent by the plexiglass enclosures indicated that these production estimates may be low by one-third to one-half. These results suggest that concern for ethylene build-up in a contained atmosphere should be greatest when growing lettuce, and less when growing wheat or potato.

  12. Combustion characteristics of hydrogen-carbon monoxide based gaseous fuels

    NASA Technical Reports Server (NTRS)

    White, D. J.; Kubasco, A. J.; Lecren, R. T.; Notardonato, J. J.

    1982-01-01

    The results of trials with a staged combustor designed to use coal-derived gaseous fuels and reduce the NO(x) emissions from nitrogen-bound fuels to 75 ppm and 37 ppm without bound nitrogen in 15% O2 are reported. The combustor was outfitted with primary zone regenerative cooling, wherein the air cooling the primary zone was passed into the combustor at 900 F and mixed with the fuel. The increase in the primary air inlet temperature eliminated flashback and autoignition, lowered the levels of CO, unburned hydrocarbons, and smoke, and kept combustion efficiencies to the 99% level. The combustor was also equipped with dual fuel injection to test various combinations of liquid/gas fuel mixtures. Low NO(x) emissions were produced burning both Lurgi and Winkler gases, regardless of the inlet pressure and temperature conditions. Evaluation of methanation of medium energy gases is recommended for providing a fuel with low NO(x) characteristics.

  13. On-board measurements of gaseous pollutant emission characteristics under real driving conditions from light-duty diesel vehicles in Chinese cities.

    PubMed

    Wang, Gang; Cheng, Shuiyuan; Lang, Jianlei; Li, Song; Tian, Liang

    2016-08-01

    A total of 15 light-duty diesel vehicles (LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons (HC) and nitrogen oxides (NOx) at different speeds, chemical species profiles and ozone formation potential (OFP) of volatile organic compounds (VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOx had been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOx emissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%-45.2%, followed by aromatics and alkenes. The most abundant species were propene, ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity (MIR) method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%-91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and 1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene. PMID:27521933

  14. 14 CFR 34.71 - Compliance with gaseous emission standards.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This... TRANSPORTATION AIRCRAFT FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Test Procedures for Engine Exhaust Gaseous Emissions (Aircraft and Aircraft Gas Turbine Engines) §...

  15. 14 CFR 34.71 - Compliance with gaseous emission standards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This... TRANSPORTATION AIRCRAFT FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Test Procedures for Engine Exhaust Gaseous Emissions (Aircraft and Aircraft Gas Turbine Engines) §...

  16. 14 CFR 34.71 - Compliance with gaseous emission standards.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This... TRANSPORTATION AIRCRAFT FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Test Procedures for Engine Exhaust Gaseous Emissions (Aircraft and Aircraft Gas Turbine Engines) §...

  17. Gaseous emissions from Canadian boreal forest fires

    NASA Technical Reports Server (NTRS)

    Cofer, Wesley R., III; Levine, Joel S.; Winstead, Edward L.; Stocks, Brian J.

    1990-01-01

    CO2-normalized emission ratios for carbon monoxide (CO), hydrogen (H2), methane (CH4), total nonmethane hydrocarbons (TNMHC), and nitrous oxide (N2O) were determined from smoke samples collected during low-altitude helicopter flights over two prescribed fires in northern Ontario, Canada. The emission ratios determined from these prescribed boreal forest fires are compared to emission ratios determined over two graminoid (grass) wetlands fires in central Florida and are found to be substantially higher (elevated levels of reduced gas production relative to CO2) during all stages of combustion. These results argue strongly for the need to characterize biomass burning emissions from the major global vegetation/ecosystems in order to couple combustion emissions to their vegetation/ecosystem type.

  18. Gaseous Tracers in Receptor Modeling: Methyl - Emission from Wood Combustion

    NASA Astrophysics Data System (ADS)

    Edgerton, Sylvia Anne

    The model and the statistical and experimental techniques for using gaseous species to trace sources of particulate air pollution are developed. The model is implemented in a simple environment and the results are compared with those obtained from the concurrent application of other models. In particular, measurements of elevated concentrations of the gas methyl chloride, CH(,3)Cl, in the Portland, Oregon area are used to quantify the contribution of residential wood combustion to fine particulate pollution. The method requires accurate measurements of the gas to aerosol ratios in the source emissions and knowledge of all sources contributing to the ambient concentrations of the gases. The source emission factors for the ratio of CH(,3)Cl to aerosol from woodburning are presented for different types of wood and burn conditions along with measurements of the background concentrations of CH(,3)Cl at both an urban and a remote global site. The advantages of using gaseous tracers to apportion the sources of particulate pollution include: (1) the continuous in situ monitoring which provides real time estimates of the source contributions and therefore of personal exposures, and (2) the inclusion of a gaseous species, such as CH(,3)Cl for woodburning, in the multicomponent Chemical Mass Balance (CMB) receptor model can help distinguish source contributions among sources with similar elemental characterizations. The results of using CH(,3)Cl to estimate the contribution of woodburning to particulate air pollution show that the evening, wintertime averaged concentrations of fine particles from woodburning ranges from 10 (mu)g/m('3) in a hilly, windy neighborhood to 50-73 (mu)g/m('3) in neighborhoods on low terrain subject to poor meteorological dispersion. Woodburning emissions may be a major cause of the nonattainment of air quality standards in many urban areas. The uncertainty of the woodburning contribution using CH(,3)Cl measurements is generally less than 30%. The

  19. Particle and gaseous emissions from individual diesel and CNG buses

    NASA Astrophysics Data System (ADS)

    Hallquist, Å. M.; Jerksjö, M.; Fallgren, H.; Westerlund, J.; Sjödin, Å.

    2013-05-01

    In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III-V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel-1. In the accelerating mode, size-resolved emission factors (EFs) showed unimodal number size distributions with peak diameters of 70-90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)-1 and for the CNG buses 41 ± 26 g (kg

  20. Particle and gaseous emissions from individual diesel and CNG buses

    NASA Astrophysics Data System (ADS)

    Hallquist, Å. M.; Jerksjö, M.; Fallgren, H.; Westerlund, J.; Sjödin, Å.

    2012-10-01

    In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA 3.1. The buses studied were diesel-fuelled Euro II-V and CNG-fuelled Enhanced Environmental Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 8.0 ± 3.1 × 1014, EFPN, no DPF =2.8 ± 1.6 × 1015 and EFPN, CNG = 7.8 ± 5.7 × 1015 (kg fuel-1). In the accelerating mode size-resolved EFs showed unimodal number size distributions with peak diameters of 70-90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)-1 and for the CNG buses 41 ± 26 g (kg fuel)-1. An anti

  1. Reduction of gaseous pollutant emissions from gas turbine combustors using hydrogen-enriched jet fuel

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1976-01-01

    Recent progress in an evaluation of the applicability of the hydrogen enrichment concept to achieve ultralow gaseous pollutant emission from gas turbine combustion systems is described. The target emission indexes for the program are 1.0 for oxides of nitrogen and carbon monoxide, and 0.5 for unburned hydrocarbons. The basic concept utilizes premixed molecular hydrogen, conventional jet fuel, and air to depress the lean flammability limit of the mixed fuel. This is shown to permit very lean combustion with its low NOx production while simulataneously providing an increased flame stability margin with which to maintain low CO and HC emission. Experimental emission characteristics and selected analytical results are presented for a cylindrical research combustor designed for operation with inlet-air state conditions typical for a 30:1 compression ratio, high bypass ratio, turbofan commercial engine.

  2. 40 CFR 60.1720 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What continuous emission monitoring systems must I install for gaseous pollutants? 60.1720 Section 60.1720 Protection of Environment... emission monitoring systems must I install for gaseous pollutants? (a) You must install,...

  3. 40 CFR 60.1230 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What continuous emission monitoring systems must I install for gaseous pollutants? 60.1230 Section 60.1230 Protection of Environment... gaseous pollutants? (a) You must install, calibrate, maintain, and operate continuous emission...

  4. Gaseous and particulate emission profiles during controlled rice straw burning

    NASA Astrophysics Data System (ADS)

    Sanchis, E.; Ferrer, M.; Calvet, S.; Coscollà, C.; Yusà, V.; Cambra-López, M.

    2014-12-01

    Burning of rice straw can emit considerable amounts of atmospheric pollutants. We evaluated the effect of rice straw moisture content (5%, 10%, and 20%) on the emission of carbon dioxide (CO2) and on the organic and inorganic constituents of released particulate matter (PM): dioxins, heavy metals, and polycyclic aromatic hydrocarbons (PAHs). Four burning tests were conducted per moisture treatment using the open chamber method. Additionally, combustion characteristics, including burning stages, durations, temperature, and relative humidity, were recorded. Burning tests showed flaming and smoldering stages were significantly longer in 20% moisture treatment (P < 0.05) compared with the rest. The amount of burned straw and ashes decreased with increasing straw moisture content (P < 0.001). Carbon dioxide was the main product obtained during combustion with emission values ranging from 692 g CO2 kg dry straw-1 (10% moisture content) to 835 g CO2 kg dry straw-1 (20% moisture content). Emission factors for PM were the highest in 20% moisture treatment (P < 0.005). Fine PM (PM2.5) accounted for more than 60% of total PM mass. Emission factors for dioxins increased with straw moisture content, being the highest in 20% moisture treatment, although showing a wide variability among burning tests (P > 0.05). Emissions factors for heavy metals were low and similar among moisture treatments (P > 0.05). Emission factors for individual PAHs were generally higher in 20% moisture treatment. Overall, emission factors of atmospheric pollutants measured in our study were higher in the 20% moisture content. This difference could be attributed to the incomplete combustion at higher levels of rice straw moisture content. According to our results, rice straw burning should be done after straw drying and under minimal moisture conditions to lower pollutant emission levels.

  5. 40 CFR 86.237-94 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Dynamometer test run, gaseous... test run, gaseous emissions. (a) The complete dynamometer test consists of a cold start drive of... terminates after the first period (505 seconds) is run. (d) The provisions of § 86.137(b) apply to...

  6. 40 CFR 86.237-94 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Dynamometer test run, gaseous... test run, gaseous emissions. (a) The complete dynamometer test consists of a cold start drive of... terminates after the first period (505 seconds) is run. (d) The provisions of § 86.137(b) apply to...

  7. 40 CFR 86.237-94 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Dynamometer test run, gaseous... test run, gaseous emissions. (a) The complete dynamometer test consists of a cold start drive of... terminates after the first period (505 seconds) is run. (d) The provisions of § 86.137(b) apply to...

  8. 40 CFR 86.237-94 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Dynamometer test run, gaseous... test run, gaseous emissions. (a) The complete dynamometer test consists of a cold start drive of... terminates after the first period (505 seconds) is run. (d) The provisions of § 86.137(b) apply to...

  9. 40 CFR 86.137-90 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Dynamometer test run, gaseous and particulate emissions. 86.137-90 Section 86.137-90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977...

  10. 40 CFR 86.237-08 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Dynamometer test run, gaseous emissions. 86.237-08 Section 86.237-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model...

  11. 40 CFR 86.237-08 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Dynamometer test run, gaseous emissions. 86.237-08 Section 86.237-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model...

  12. 40 CFR 86.237-08 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Dynamometer test run, gaseous emissions. 86.237-08 Section 86.237-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model...

  13. Gaseous emissions during concurrent combustion of biomass and non-recyclable municipal solid waste

    PubMed Central

    2011-01-01

    Background Biomass and municipal solid waste offer sustainable sources of energy; for example to meet heat and electricity demand in the form of combined cooling, heat and power. Combustion of biomass has a lesser impact than solid fossil fuels (e.g. coal) upon gas pollutant emissions, whilst energy recovery from municipal solid waste is a beneficial component of an integrated, sustainable waste management programme. Concurrent combustion of these fuels using a fluidised bed combustor may be a successful method of overcoming some of the disadvantages of biomass (high fuel supply and distribution costs, combustion characteristics) and characteristics of municipal solid waste (heterogeneous content, conflict with materials recycling). It should be considered that combustion of municipal solid waste may be a financially attractive disposal route if a 'gate fee' value exists for accepting waste for combustion, which will reduce the net cost of utilising relatively more expensive biomass fuels. Results Emissions of nitrogen monoxide and sulphur dioxide for combustion of biomass are suppressed after substitution of biomass for municipal solid waste materials as the input fuel mixture. Interactions between these and other pollutants such as hydrogen chloride, nitrous oxide and carbon monoxide indicate complex, competing reactions occur between intermediates of these compounds to determine final resultant emissions. Conclusions Fluidised bed concurrent combustion is an appropriate technique to exploit biomass and municipal solid waste resources, without the use of fossil fuels. The addition of municipal solid waste to biomass combustion has the effect of reducing emissions of some gaseous pollutants. PMID:21284885

  14. Investigation of thermal and environmental characteristics of combustion of gaseous fuels

    NASA Astrophysics Data System (ADS)

    Vetkin, A. V.; Suris, A. L.

    2015-03-01

    Numerical investigations are fulfilled for some thermal and environmental characteristics of combustion of gaseous fuels used at present in tube furnaces of petroleum refineries. The effect of the fuel composition on these characteristics is shown and probable consequences of the substitution of natural gas to other types of fuels. Methane, ethane, propane, butane, propylene, and hydrogen are considered for comparison, which in most cases are constituents of the composition of the fuel burnt in furnaces. The effect of the fuel type, its associated combustion temperature, combustion product emissivity, temperature of combustion chamber walls, mean beam length, and heat release on the variation in the radiant heat flux within the radiant chamber of furnaces is investigated. The effect of flame characteristics, which are determined by the presence of diffusion combustion zones formed by burners used at present in furnaces for reducing nitrogen oxides emission, is analyzed. The effect of the fuel type on the equilibrium NO concentration is also investigated. The investigations were carried out both at arbitrary given gas temperatures and at effective temperatures dependent on the adiabatic combustion temperature and the temperature at the chamber output and determined based on solving a set of equations at various heat-release rates of the combustion chamber.

  15. 14 CFR 34.64 - Sampling and analytical procedures for measuring gaseous exhaust emissions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This document can be obtained from the... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE... Turbine Engines) § 34.64 Sampling and analytical procedures for measuring gaseous exhaust emissions....

  16. 14 CFR 34.64 - Sampling and analytical procedures for measuring gaseous exhaust emissions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This document can be obtained from the... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE... Turbine Engines) § 34.64 Sampling and analytical procedures for measuring gaseous exhaust emissions....

  17. 14 CFR 34.64 - Sampling and analytical procedures for measuring gaseous exhaust emissions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. This document can be obtained from the... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE... Turbine Engines) § 34.64 Sampling and analytical procedures for measuring gaseous exhaust emissions....

  18. The influence of ozone on atmospheric emissions of gaseous elemental mercury and reactive gaseous mercury from substrates

    USGS Publications Warehouse

    Engle, M.A.; Sexauer, Gustin M.; Lindberg, S.E.; Gertler, A.W.; Ariya, P.A.

    2005-01-01

    Experiments were performed to investigate the effect of ozone (O 3) on mercury (Hg) emission from a variety of Hg-bearing substrates. Substrates with Hg(II) as the dominant Hg phase exhibited a 1.7 to 51-fold increase in elemental Hg (Hgo) flux and a 1.3 to 8.6-fold increase in reactive gaseous mercury (RGM) flux in the presence of O3-enriched clean (50 ppb O3; 8 substrates) and ambient air (up to ???70 ppb O3; 6 substrates), relative to clean air (oxidant and Hg free air). In contrast, Hgo fluxes from two artificially Hgo-amended substrates decreased by more than 75% during exposure to O3-enriched clean air relative to clean air. Reactive gaseous mercury emissions from Hg o-amended substrates increased immediately after exposure to O 3 but then decreased rapidly. These experimental results demonstrate that O3 is very important in controlling Hg emissions from substrates. The chemical mechanisms that produced these trends are not known but potentially involve heterogenous reactions between O3, the substrate, and Hg. Our experiments suggest they are not homogenous gas-phase reactions. Comparison of the influence of O3 versus light on increasing Hgo emissions from dry Hg(II)-bearing substrates demonstrated that they have a similar amount of influence although O3 appeared to be slightly more dominant. Experiments using water-saturated substrates showed that the presence of high-substrate moisture content minimizes reactions between atmospheric O3 and substrate-bound Hg. Using conservative calculations developed in this paper, we conclude that because O3 concentrations have roughly doubled in the last 100 years, this could have increased Hgo emissions from terrestrial substrates by 65-72%. ?? 2005 Elsevier Ltd. All rights reserved.

  19. Gaseous emissions from outdoor concrete yards used by livestock

    NASA Astrophysics Data System (ADS)

    Misselbrook, T. H.; Webb, J.; Chadwick, D. R.; Ellis, S.; Pain, B. F.

    Measurements of ammonia (NH 3), nitrous oxide (N 2O) and methane (CH 4) were made from 11 outdoor concrete yards used by livestock. Measurements of NH 3 emission were made using the equilibrium concentration technique while closed chambers were used to measure N 2O and CH 4 emissions. Outdoor yards used by livestock proved to be an important source of NH 3 emission. Greatest emission rates were measured from dairy cow feeding yards, with a mean of 690 mg NH 3-N m -2 h -1. Smaller emission rates were measured from sheep handling areas, dairy cow collecting yards, beef feeding yards and a pig loading area, with respective mean emission rates of 440, 280, 220 and 140 mg NH 3-N m -2 h -1. Emission rates of N 2O and CH 4 were much smaller and for CH 4, in particular, emission rates were influenced greatly by the presence or absence of dung on the measurement area.

  20. Spontaneous ignition characteristics of gaseous hydrocarbon-air mixtures

    NASA Technical Reports Server (NTRS)

    Freeman, G.; Lefebvre, A. H.

    1984-01-01

    Experiments are conducted to determine the spontaneous ignition delay times of gaseous propane, kerosine vapor, and n-heptane vapor in mixtures with air, and oxygen-enriched air, at atmospheric pressure. Over a range of equivalence ratios from 0.2 to 0.8 it is found that ignition delay times are sensibly independent of fuel concentration. However, the results indicate a strong dependence of delay times on oxygen concentration. The experimental data for kerosine and propane demonstrate very close agreement with the results obtained previously by Mullins and Lezberg respectively.

  1. Emissions of Nanoparticles and Gaseous Material from 3D Printer Operation.

    PubMed

    Kim, Yuna; Yoon, Chungsik; Ham, Seunghon; Park, Jihoon; Kim, Songha; Kwon, Ohhun; Tsai, Perng-Jy

    2015-10-20

    This study evaluated the emissions characteristics of hazardous material during fused deposition modeling type 3D printing. Particulate and gaseous materials were measured before, during, and after 3D printing in an exposure chamber. One ABS and two PLA (PLA1 and PLA2) cartridges were tested three times. For online monitoring, a scanning mobility particle sizer, light scattering instrument, and total volatile organic compound (TVOC) monitor were employed and a polycarbonate filter and various adsorbent tubes were used for offline sampling. The particle concentration of 3D printing using ABS material was 33-38 times higher than when PLA materials were used. Most particles were nanosize (<100 nm) during ABS (96%) and PLA1 (98%) use, but only 12% were nanosize for PLA2. The emissions rates were 1.61 × 10(10) ea/min and 1.67 × 10(11) ea/g cartridge with the ABS cartridge and 4.27-4.89 × 10(8) ea/min and 3.77-3.91 × 10(9) ea/g cartridge with the PLA cartridge. TVOCs were also emitted when the ABS was used (GM; 155 ppb, GSD; 3.4), but not when the PLA cartridges were used. Our results suggest that more research and sophisticated control methods, including the use of less harmful materials, blocking emitted containments, and using filters or adsorbents, should be implemented. PMID:26402038

  2. 40 CFR 87.71 - Compliance with gaseous emission standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... standard by an aircraft engine shall be determined by comparing the pollutant level in grams/kilonewton/thrust/cycle or grams/kilowatt/cycle as calculated in § 87.64 with the applicable emission standard...

  3. Emissions calculated from particulate matter and gaseous ammonia measurements from a commercial dairy in California, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emission rates and factors for particulate matter (PM) and gaseous ammonia (NH3) were estimated from measurements taken at a dairy in California, USA in June 2008. Concentration measurements were made using both point and remote sensors. Filter-based PM samplers and OPCs characterized aerodynamic an...

  4. Modeling of carbon and nitrogen gaseous emissions from cattle manure compost windrows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Windrow composting of cattle manure is a significant source of gaseous emissions, which include ammonia (NH3) and the greenhouse gases (GHGs) of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). A manure compost model was developed to simulate carbon (C) and nitrogen (N) processes includ...

  5. 40 CFR 86.137-96 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Dynamometer test run, gaseous and particulate emissions. 86.137-96 Section 86.137-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-96 Dynamometer test run,...

  6. 40 CFR 86.137-96 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Dynamometer test run, gaseous and particulate emissions. 86.137-96 Section 86.137-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-96 Dynamometer test run,...

  7. 40 CFR 86.137-96 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Dynamometer test run, gaseous and particulate emissions. 86.137-96 Section 86.137-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-96 Dynamometer test run,...

  8. 40 CFR 86.137-96 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Dynamometer test run, gaseous and particulate emissions. 86.137-96 Section 86.137-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-96 Dynamometer test run,...

  9. 40 CFR 62.15175 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... emission monitoring system according to the “Monitoring Requirements” in § 60.13 of subpart A of 40 CFR... subpart A of 40 CFR part 60. ... systems must I install for gaseous pollutants? 62.15175 Section 62.15175 Protection of...

  10. METHOD 25 - DETERMINATION OF TOTAL GASEOUS NON-METHANE ORGANIC EMISSIONS AS CARBON FROM STATIONARY SOURCES

    EPA Science Inventory

    Section 3.17 describes the procedures and specifications for determining volatile organic compounds as total gaseous non-methane organics from stationary sources. n emission sample is withdrawn from the stack at a constant rate through a heated filter and a chilled condensate tra...

  11. CHARACTERIZATION OF THE FINE PARTICLE AND GASEOUS EMISSIONS DURING SCHOOL BUS IDLING

    EPA Science Inventory

    The particulate matter (PM) and gaseous emissions from six diesel school buses were determined over a simulated idling period typical of schools in the northeastern U.S. Testing was conducted for both continuous idle and hot restart conditions using particle and gas analyzers. Th...

  12. GASEOUS AND PARTICULATE EMISSIONS FROM GASOLINE- AND DIESEL-POWERED HEAVY-DUTY TRUCKS

    EPA Science Inventory

    Gaseous and particulate emission rates from seven class 2B, one class 5 and six class 6 heavy-duty gasoline- and diesel-powered trucks were determined using transient chassis dynamometer test procedures. All vehicles were tested at approximately 70% of their rated gross vehicle w...

  13. Effects of anaerobic digestion and aerobic treatment on gaseous emissions from dairy manure storages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of anaerobic digestion and aerobic treatment on the reduction of gaseous emissions from dairy manure storages were evaluated in this study. Screened dairy manure containing 3.5% volatile solids (VS) was either anaerobically digested or aerobically treated prior to storage in air-tight vessel...

  14. MODELS AND STATISTICAL METHODS FOR GASEOUS EMISSION TESTING OF FINITE SOURCES IN WELL-MIXED CHAMBERS

    EPA Science Inventory

    The paper proposes two families of mathematical models to represent either the concentration of a gaseous emission in (or the accumulated amount exiting from) a well-mixed, environmentally controlled test chamber. A thin film model, which seems applicable to such sources as carpe...

  15. 40 CFR 60.1230 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What continuous emission monitoring systems must I install for gaseous pollutants? 60.1230 Section 60.1230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW...

  16. 40 CFR 60.1720 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What continuous emission monitoring systems must I install for gaseous pollutants? 60.1720 Section 60.1720 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW...

  17. 40 CFR 86.237-08 - Dynamometer test run, gaseous emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.237-08 Dynamometer test run, gaseous emissions. (a) The complete dynamometer test consists of a cold start drive of...) The vehicle is allowed to stand on the dynamometer during the ten minute time period between the...

  18. Infrared emission from photo-excited gaseous benzene: detection with a new home-made spectrometer

    NASA Astrophysics Data System (ADS)

    Féraud, G.; Carpentier, Y.; Pino, T.; Longval, Y.; Dartois, E.; Chamaillé, T.; Vasquez, R.; Vincent, J.; Parneix, P.; Falvo, C.; Bréchignac, Ph.

    2012-02-01

    The infrared fluorescence decay and the dispersed emission spectrum are presented for gaseous benzene following 193 nm laser excitation. They were measured with FIREFLY (Fluorescence in the InfraRed from Excited FLYing molecules), a new home-made spectrometer. Redshift and redtail in the CH stretch emission spectra (3.3 μm region) demonstrate that anharmonicity plays a key role when dealing with high internal energies, as it is the case in the interstellar medium.

  19. Combustion characteristics of hydrogen. Carbon monoxide based gaseous fuels

    NASA Astrophysics Data System (ADS)

    Notardonato, J. J.; White, D. J.; Kubasco, A. J.; Lecren, R. T.

    1981-10-01

    An experimental rig program was conducted with the objective of evaluating the combuston performance of a family of fuel gases based on a mixture of hydrogen and carbon monoxide. These gases, in addition to being members of a family, were also representative of those secondary fuels that could be produced from coal by various gasification schemes. In particular, simulated Winkler, Lurgi, and Blue-water low and medium energy content gases were used as fuels in the experimental combustor rig. The combustor used was originally designed as a low NOx rich-lean system for burning liquid fuels with high bound nitrogen levels. When used with the above gaseous fuels this combustor was operated in a lean-lean mode with ultra long residence times. The Blue-water gas was also operated in a rich-lean mode. The results of these tests indicate the possibility of the existence of an 'optimum' gas turbine hydrogen - carbon monoxide based secondary fuel. Such a fuel would exhibit NOx and high efficiency over the entire engine operating range. It would also have sufficient stability range to allow normal light-off and engine acceleration. Solar Turbines Incorporated would like to emphasize that the results presented here have been obtained with experimental rig combustors. The technologies generated could, however, be utilized in future commercial gas turbines.

  20. Combustion characteristics of hydrogen. Carbon monoxide based gaseous fuels

    NASA Technical Reports Server (NTRS)

    Notardonato, J. J.; White, D. J.; Kubasco, A. J.; Lecren, R. T.

    1981-01-01

    An experimental rig program was conducted with the objective of evaluating the combuston performance of a family of fuel gases based on a mixture of hydrogen and carbon monoxide. These gases, in addition to being members of a family, were also representative of those secondary fuels that could be produced from coal by various gasification schemes. In particular, simulated Winkler, Lurgi, and Blue-water low and medium energy content gases were used as fuels in the experimental combustor rig. The combustor used was originally designed as a low NOx rich-lean system for burning liquid fuels with high bound nitrogen levels. When used with the above gaseous fuels this combustor was operated in a lean-lean mode with ultra long residence times. The Blue-water gas was also operated in a rich-lean mode. The results of these tests indicate the possibility of the existence of an 'optimum' gas turbine hydrogen - carbon monoxide based secondary fuel. Such a fuel would exhibit NOx and high efficiency over the entire engine operating range. It would also have sufficient stability range to allow normal light-off and engine acceleration. Solar Turbines Incorporated would like to emphasize that the results presented here have been obtained with experimental rig combustors. The technologies generated could, however, be utilized in future commercial gas turbines.

  1. Gaseous and bioaerosol emissions from municipal wastewater treatment plants.

    PubMed

    Seetha, N; Bhargava, Renu; Gurjar, B R

    2013-10-01

    Wastewater treatment plants (WWTPs) are identified as potential emission sources of greenhouse gases (GHGs) and bioaerosols. This paper reviews and analyse the potential sources of GHGs and bioaerosols from different unit operations and processes of WWTPs. Aeration tanks of activated sludge process (ASP) are found to be the most important sources of GHGs as well as bioaerosol emissions. Nitrification and denitrification processes are found to be important sources of nitrous oxide (N2O) emissions. To minimize the N2O emissions from WWTPs, dissolved oxygen (DO) concentration should be kept greater than 2 mg/L in nitrification process, whereas purely anoxic condition (0 mg/L DO) is required in denitrification process. Diffused aeration emits fewer microbes into the air than surface aerators. It is observed that fixed-film processes emit microbes by two orders of magnitude less than aeration tanks. The various WWTPs discussed in this study used different methods of treatment sample collection and species of microorganisms studied. It is realised that the standardisation of the microorganisms to be analysed and methods of sample collection needs to be done. It is also found that from the microbiological point of view, there is no clean air in the vicinity of a WWTP. PMID:25906597

  2. An Extensive Survey of Gaseous Emissions from Rice Paddy Agriculture

    NASA Astrophysics Data System (ADS)

    Redeker, K. R.; Meinardi, S.; Blake, D.; Sass, R.; Cicerone, R.

    2002-05-01

    Rice agriculture currently occupies nearly 1% of the available land surface area of the globe. Increased population over the next few decades will drive the need for further expansion of global agriculture. Understanding atmospheric chemistry and climate change requires us to study small changes in relatively poorly quantified gases. In order to fully describe the effects of changing land use it is imperative to understand the relative shift in emissions post and prior to agricultural use for all relevant compounds. During the 2000 growing season we sampled over a commercial rice field in Houston TX. Our study surveyed over 45 separate compounds (up to C7), covering alkanes, alkenes, aromatics, isoprene, DMS, halocarbons, CFCs, and alkyl nitrates. We compare and include results from previous studies to complement our emissions. We include emissions from control plots (unplanted with rice, but flooded) that allows us to determine whether emissions are rice-plant dependent or are inherent in the rice paddy environment itself. Biomass burning estimates are calculated for fields where residue burning is practiced.

  3. Gaseous emissions from management of solid waste: a systematic review.

    PubMed

    Pardo, Guillermo; Moral, Raúl; Aguilera, Eduardo; Del Prado, Agustín

    2015-03-01

    The establishment of sustainable soil waste management practices implies minimizing their environmental losses associated with climate change (greenhouse gases: GHGs) and ecosystems acidification (ammonia: NH3 ). Although a number of management strategies for solid waste management have been investigated to quantify nitrogen (N) and carbon (C) losses in relation to varied environmental and operational conditions, their overall effect is still uncertain. In this context, we have analyzed the current scientific information through a systematic review. We quantified the response of GHG emissions, NH3 emissions, and total N losses to different solid waste management strategies (conventional solid storage, turned composting, forced aerated composting, covering, compaction, addition/substitution of bulking agents and the use of additives). Our study is based on a meta-analysis of 50 research articles involving 304 observations. Our results indicated that improving the structure of the pile (waste or manure heap) via addition or substitution of certain bulking agents significantly reduced nitrous oxide (N2 O) and methane (CH4 ) emissions by 53% and 71%, respectively. Turned composting systems, unlike forced aerated composted systems, showed potential for reducing GHGs (N2 O: 50% and CH4 : 71%). Bulking agents and both composting systems involved a certain degree of pollution swapping as they significantly promoted NH3 emissions by 35%, 54%, and 121% for bulking agents, turned and forced aerated composting, respectively. Strategies based on the restriction of O2 supply, such as covering or compaction, did not show significant effects on reducing GHGs but substantially decreased NH3 emissions by 61% and 54% for covering and compaction, respectively. The use of specific additives significantly reduced NH3 losses by 69%. Our meta-analysis suggested that there is enough evidence to refine future Intergovernmental Panel on Climate Change (IPCC) methodologies from solid waste

  4. Gaseous emissions from management of solid waste: a systematic review

    PubMed Central

    Pardo, Guillermo; Moral, Raúl; Aguilera, Eduardo; del Prado, Agustín

    2015-01-01

    The establishment of sustainable soil waste management practices implies minimizing their environmental losses associated with climate change (greenhouse gases: GHGs) and ecosystems acidification (ammonia: NH3). Although a number of management strategies for solid waste management have been investigated to quantify nitrogen (N) and carbon (C) losses in relation to varied environmental and operational conditions, their overall effect is still uncertain. In this context, we have analyzed the current scientific information through a systematic review. We quantified the response of GHG emissions, NH3 emissions, and total N losses to different solid waste management strategies (conventional solid storage, turned composting, forced aerated composting, covering, compaction, addition/substitution of bulking agents and the use of additives). Our study is based on a meta-analysis of 50 research articles involving 304 observations. Our results indicated that improving the structure of the pile (waste or manure heap) via addition or substitution of certain bulking agents significantly reduced nitrous oxide (N2O) and methane (CH4) emissions by 53% and 71%, respectively. Turned composting systems, unlike forced aerated composted systems, showed potential for reducing GHGs (N2O: 50% and CH4: 71%). Bulking agents and both composting systems involved a certain degree of pollution swapping as they significantly promoted NH3 emissions by 35%, 54%, and 121% for bulking agents, turned and forced aerated composting, respectively. Strategies based on the restriction of O2 supply, such as covering or compaction, did not show significant effects on reducing GHGs but substantially decreased NH3 emissions by 61% and 54% for covering and compaction, respectively. The use of specific additives significantly reduced NH3 losses by 69%. Our meta-analysis suggested that there is enough evidence to refine future Intergovernmental Panel on Climate Change (IPCC) methodologies from solid waste

  5. Particulate and gaseous emissions when welding aluminum alloys.

    PubMed

    Cole, Homer; Epstein, Seymour; Peace, Jon

    2007-09-01

    Fabrication and repair of aluminum components and structures commonly involves the use of electric arc welding. The interaction of the arc and the metal being welded generates ultraviolet radiation, metallic oxides, fumes, and gases. Aluminum is seldom used as the pure metal but is often alloyed with other metals to improve strength and other physical properties. Therefore, the exact composition of any emissions will depend on the welding process and the particular aluminum alloy being welded. To quantify such emissions, The Aluminum Association sponsored several studies to characterize arc welding emissions by the gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) processes for various combinations of base and filler alloys. In all cases, the tests were conducted under conditions that could be found in a production weld shop without forced ventilation. The concentrations of each analyte that a welder could be exposed to were greatly affected by the welding process, the composition of the base and filler alloys, the position of the welder, and the welding helmet. The results obtained can be used by employers to identify and control potential hazards associated with the welding of aluminum alloys and can provide the basis for hazard communication to employees involved in the welding of these alloys. PMID:17620189

  6. Characterization of particulate matter and gaseous emissions of a C-130H aircraft.

    PubMed

    Corporan, Edwin; Quick, Adam; DeWitt, Matthew J

    2008-04-01

    The gaseous and nonvolatile particulate matter (PM) emissions of two T56-A-15 turboprop engines of a C-130H aircraft stationed at the 123rd Airlift Wing in the Kentucky Air National Guard were characterized. The emissions campaign supports the Strategic Environmental Research and Development Program (SERDP) project WP-1401 to determine emissions factors from military aircraft. The purpose of the project is to develop a comprehensive emissions measurement program using both conventional and advanced techniques to determine emissions factors of pollutants, and to investigate the spatial and temporal evolutions of the exhaust plumes from fixed and rotating wing military aircraft. Standard practices for the measurement of gaseous emissions from aircraft have been well established; however, there is no certified methodology for the measurement of aircraft PM emissions. In this study, several conventional instruments were used to physically characterize and quantify the PM emissions from the two turboprop engines. Emissions samples were extracted from the engine exit plane and transported to the analytical instrumentation via heated lines. Multiple sampling probes were used to assess the spatial variation and obtain a representative average of the engine emissions. Particle concentrations, size distributions, and mass emissions were measured using commercially available aerosol instruments. Engine smoke numbers were determined using established Society of Automotive Engineers (SAE) practices, and gaseous species were quantified via a Fourier-transform infrared-based gas analyzer. The engines were tested at five power settings, from idle to take-off power, to cover a wide range of operating conditions. Average corrected particle numbers (PNs) of (6.4-14.3) x 10(7) particles per cm3 and PN emission indices (EI) from 3.5 x 10(15) to 10.0 x 10(15) particles per kg-fuel were observed. The highest PN EI were observed for the idle power conditions. The mean particle diameter

  7. Particle- and Gaseous Emissions from an LNG Powered Ship.

    PubMed

    Anderson, Maria; Salo, Kent; Fridell, Erik

    2015-10-20

    Measurements of particle number and mass concentrations and number size distribution of particles from a ship running on liquefied natural gas (LNG) were made on-board a ship with dual-fuel engines installed. Today there is a large interest in LNG as a marine fuel, as a means to comply with sulfur and NOX regulations. Particles were studied in a wide size range together with measurements of other exhaust gases under different engine loads and different mixtures of LNG and marine gas oil. Results from these measurements show that emissions of particles, NOX, and CO2 are considerably lower for LNG compared to present marine fuel oils. Emitted particles were mainly of volatile character and mainly had diameters below 50 nm. Number size distribution for LNG showed a distinct peak at 9-10 nm and a part of a peak at diameter 6 nm and below. Emissions of total hydrocarbons and carbon monoxide are higher for LNG compared to present marine fuel oils, which points to the importance of considering the methane slip from combustion of LNG. PMID:26422536

  8. Measurement of gaseous emissions from a turbofan engine at simulated altitude conditions

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.; Biaglow, J. A.

    1974-01-01

    Gaseous emission from a TFE 731-2 turbofan engine were measured over a range of fuel-air ratios from idle to full power at simulated from near sea level to 13,200 m. Carbon monoxide and unburned hydrocarbon emissions were highest at idle and lowest at high power settings; oxides of nitrogen exhibited the reverse trend. Carbon monoxide and unburned hydrocarbon levels decreased with increasing altitude. Oxides of nitrogen emissions were successfully correlated by a parametric group of combustor operating variables.

  9. Gaseous and particulate emissions from a DC arc melter.

    PubMed

    Overcamp, Thomas J; Speer, Matthew P; Griner, Stewart J; Cash, Douglas M

    2003-01-01

    Tests treating soils contaminated with metal compounds and radionuclide surrogates were conducted in a DC arc melter. The soil melted, and glassy or ceramic waste forms with a separate metal phase were produced. Tests were run in the melter plenum with either air or N2 purge gases. In addition to nitrogen, the primary emissions of gases were CO2, CO, oxygen, methane, and oxides of nitrogen (NO(x)). Although the gas flow through the melter was low, the particulate concentrations ranged from 32 to 145 g/m3. Cerium, a nonradioactive surrogate for plutonium and uranium, was not enriched in the particulate matter (PM). The PM was enriched in cesium and highly enriched in lead. PMID:12568249

  10. Gaseous emissions during the solid state fermentation of different wastes for enzyme production at pilot scale.

    PubMed

    Maulini-Duran, Caterina; Abraham, Juliana; Rodríguez-Pérez, Sheila; Cerda, Alejandra; Jiménez-Peñalver, Pedro; Gea, Teresa; Barrena, Raquel; Artola, Adriana; Font, Xavier; Sánchez, Antoni

    2015-03-01

    The emissions of volatile organic compounds (VOC), CH4, N2O and NH3 during the solid state fermentation process of some selected wastes to obtain different enzymes have been determined at pilot scale. Orange peel+compost (OP), hair wastes+raw sludge (HW) and winterization residue+raw sludge (WR) have been processed in duplicate in 50 L reactors to provide emission factors and to identify the different VOC families present in exhaust gaseous emissions. Ammonia emission from HW fermentation (3.2±0.5 kg Mg(-1) dry matter) and VOC emission during OP processes (18±6 kg Mg(-1) dry matter) should be considered in an industrial application of these processes. Terpenes have been the most emitted VOC family during all the processes although the emission of sulphide molecules during HW SSF is notable. The most emitted compound was dimethyl disulfide in HW and WR processes, and limonene in the SSF of OP. PMID:25545090

  11. Measurement of gaseous emissions from an afterburning turbojet engine at simulated altitude conditions

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.

    1973-01-01

    Gaseous emissions from a J85-GE-13 turbojet engine were measured over a range of fuel-air ratios from idle to full afterburning and simulated altitudes from near sea-level to 12,800 meters (42,000 ft). Without afterburning, carbon monoxide and unburned hydrocarbon emissions were highest at idle and lowest at takeoff; oxides of nitrogen exhibited the reverse trend. With afterburning, carbon monoxide and unburned hydrocarbon emissions were greater than for military power. Carbon monoxide emissions were altitude dependent. Oxides of nitrogen emissions were less at minimum afterburning than at military power. For power levels above minimum afterburning, the oxides of nitrogen emissions were both power level and altitude dependent.

  12. Effect of dramatic land use change on gaseous pollutant emissions from biomass burning in Northeastern China

    NASA Astrophysics Data System (ADS)

    Zhao, Hongmei; Tong, Daniel Q.; Gao, Chuanyu; Wang, Guoping

    2015-02-01

    Biomass burning contributes a substantial amount of gas and particle emissions to the atmosphere. As China's breadbasket, northeast China has experienced dramatic land use change in the past century, converting approximately 55 × 104 ha of wetland into farmland to feed a rapidly growing population. This study combines measured emission factors of dominant crops (rice and soybean) and wetland plants (Calamagrostis angu-stifolia, Carex lasiocarpa, Carex pseudo-curaica) and remote sensing land use data to estimate the effect of the unprecedented land use change on gaseous pollutants emissions from biomass burning. Our biomass burning emission estimates resulting from land use changes have increased because of increased post-harvest crop residue burning and decreased burning of wetland plants. From 1986 to 2005, the total emissions of CO2, CO, CXHY, SO2 and NO have increased by 18.6%, 35.7%, 26.8%, 66.2% and 33.2%, respectively. We have found two trends in agricultural burning: increased dryland crop residue burning and decreased wetland (rice paddy) burning. Our results revealed that the large scale land use change in northeastern China has induced more active biomass-burning emissions. The regional emission inventory of gaseous pollutants derived from this work may be used to support further examination of the subsequent effects on regional climate and air quality simulations with numerical atmospheric models.

  13. Optical emission spectroscopy and shadowgraph imaging of pulsed laser plasmas generated in gaseous, liquid and supercritical CO2

    NASA Astrophysics Data System (ADS)

    Kato, Toru; Takizawa, Yoshihiko; Stauss, Sven; Baba, Motoyoshi; Suemoto, Tohru; Terashima, Kazuo

    2012-10-01

    Pulsed laser ablation (PLA) in liquids has attracted a lot of attention due to its potential for the synthesis of a wide range of nanomaterials. Contrary to PLA in vacuum, in liquids the plasma plume is confined due to the high density of the medium. This restricts the diffusion of active species and leads to rapid quenching, which limits particle growth. Compared to liquids, supercritical fluids (SCFs) possess superior transport properties and PLA in SCFs has been used for realizing chemical synthesis of nanomaterials such as diamondoids. We have investigated the dynamics of PLA (laser: Nd-YAG, wavelength 532 nm; pulse width 7 ns; frequency 10 Hz; target: carbon, nickel) in gaseous (0.1-6 MPa), liquid and supercritical CO2 (Tcrit: 304.1 K, Pcrit: 7.38 MPa). From shadowgraphs of PLA taken in gaseous, liquid and supercritical CO2, images of PLA in SCF showed characteristics similar to that of PLA in liquid. Compared to PLA in the gaseous and liquid states, optical emission spectra in SCF revealed enhanced interactions between plasma and solvent species, especially near the critical point. Owing to the high density fluctuation near the critical point, PLA in SCF is expected to lead to a better control of the synthesis of diamondoids and other nanomaterials.

  14. Development and application of a mobile laboratory for measuring emissions from diesel engines. 1. Regulated gaseous emissions.

    PubMed

    Cocker, David R; Shah, Sandip D; Johnson, Kent; Miller, J Wayne; Norbeck, Joseph M

    2004-04-01

    Information about in-use emissions from diesel engines remains a critical issue for inventory development and policy design. Toward that end, we have developed and verified the first mobile laboratory that measures on-road or real-world emissions from engines at the quality level specified in the U.S. Congress Code of Federal Regulations. This unique mobile laboratory provides information on integrated and modal regulated gaseous emission rates and integrated emission rates for speciated volatile and semivolatile organic compounds and particulate matter during real-world operation. Total emissions are captured and collected from the HDD vehicle that is pulling the mobile laboratory. While primarily intended to accumulate data from HDD vehicles, it may also be used to measure emission rates from stationary diesel sources such as back-up generators. This paper describes the development of the mobile laboratory, its measurement capabilities, and the verification process and provides the first data on total capture gaseous on-road emission measurements following the California Air Resources Board (ARB) 4-mode driving cycle, the hot urban dynamometer driving schedule (UDDS), the modified 5-mode cycle, and a 53.2-mi highway chase experiment. NOx mass emission rates (g mi(-1)) for the ARB 4-mode driving cycle, the hot UDDS driving cycle, and the chase experimentwerefoundto exceed current emission factor estimates for the engine type tested by approximately 50%. It was determined that congested traffic flow as well as "off-Federal Test Procedure cycle" emissions can lead to significant increases in per mile NOx emission rates for HDD vehicles. PMID:15112823

  15. Measuring the Effect of Fuel Chemical Structure on Particulate and Gaseous Emissions using Isotope Tracing

    SciTech Connect

    Buchholz, B A; Mueller, C J; Martin, G C; Upatnicks, A; Dibble, R W; Cheng, S

    2003-09-11

    Using accelerator mass spectrometry (AMS), a technique initially developed for radiocarbon dating and recently applied to internal combustion engines, carbon atoms within specific fuel molecules can be labeled and followed in particulate or gaseous emissions. In addition to examining the effect of fuel chemical structure on emissions, the specific source of carbon for PM can be identified if an isotope label exists in the appropriate fuel source. Existing work has focused on diesel engines, but the samples (soot collected on quartz filters or combustion gases captured in bombs or bags) are readily collected from large industrial combustors as well.

  16. High-pressure soot formation and diffusion flame extinction characteristics of gaseous and liquid fuels

    NASA Astrophysics Data System (ADS)

    Karatas, Ahmet Emre

    High-pressure soot formation and flame stability characteristics were studied experimentally in laminar diffusion flames. For the former, radially resolved soot volume fraction and temperature profiles were measured in axisymmetric co-flow laminar diffusion flames of pre-vaporized n-heptane-air, undiluted ethylene-air, and nitrogen and carbon dioxide diluted ethylene-air at elevated pressures. Abel inversion was used to re-construct radially resolved data from the line-of-sight spectral soot emission measurements. For the latter, flame extinction strain rate was measured in counterflow laminar diffusion flames of C1-4 alcohols and hydrocarbon fuels of n-heptane, n-octane, iso-octane, toluene, Jet-A, and biodiesel. The luminous flame height, as marked by visible soot radiation, of the nitrogen- and helium-diluted n-heptane and nitrogen- and carbon dioxide-diluted ethylene flames stayed constant at all pressures. In pure ethylene flames, flame heights initially increased with pressure, but changed little above 5 atm. The maximum soot yield as a function of pressure in nitrogen-diluted n-heptane diffusion flames indicate that n-heptane flames are slightly more sensitive to pressure than gaseous alkane hydrocarbon flames at least up to 7 atm. Ethylene's maximum soot volume fractions were much higher than those of ethane and n-heptane diluted with nitrogen (fuel to nitrogen mass flow ratio is about 0.5). Pressure dependence of the peak carbon conversion to soot, defined as the percentage of fuel's carbon content converted to soot, was assessed and compared to previous measurements with other gaseous fuels. Maximum soot volume fractions were consistently lower in carbon dioxide-diluted flames between 5 and 15 atm but approached similar values to those in nitrogen-diluted flames at 20 atm. This observation implies that the chemical soot suppression effect of carbon dioxide, previously demonstrated at atmospheric pressure, is also present at elevated pressures up to 15 atm

  17. Estimation and characterization of gaseous pollutant emissions from agricultural crop residue combustion in industrial and household sectors of Pakistan

    NASA Astrophysics Data System (ADS)

    Irfan, Muhammad; Riaz, Muhammad; Arif, Muhammad Saleem; Shahzad, Sher Muhammad; Saleem, Farhan; -Rahman, Naveed-ur; van den Berg, Leon; Abbas, Farhat

    2014-02-01

    A long-term energy crisis has resulted in increased combustion of biomass fuel in industrial and household sectors in Pakistan. We report results of a study on the emission characteristics of rice husk, rice straw, corncobs and bagasse since they are frequently used as biomass fuel and differed remarkably in physico-chemical and combustion characteristics. Emission concentrations and emission factors were determined experimentally by burning the biomass fuel using a burning tower. Modified combustion efficiency (MCE) of rice husk, rice straw, corncobs and bagasse was >0.97 indicating that combustion was dominated by flaming mode. Emission factors of gaseous pollutants CO, CO2, NO2, NO, NOx and SO2 for rice straw were calculated to be 17.19 ± 0.28, 1090.07 ± 24.0, 0.89 ± 0.03, 1.48 ± 0.04, 3.16 ± 0.08 and 0.38 ± 0.03 g kg-1 respectively which were significantly (p < 0.05) higher compared to those from rice husk (14.05 ± 0.18, 880.48 ± 8.99, 0.19 ± 0.01, 1.38 ± 0.02, 2.31 ± 0.04 and 0.11 ± 0.03 g kg-1), corncobs (8.63 ± 0.12, 595.44 ± 10.38, 0.16 ± 0.01, 0.70 ± 0.01, 1.23 ± 0.02 and 0.02 ± 0.00 g kg-1) and bagasse (12.39 ± 0.08, 937.03 ± 9.07, 0.36 ± 0.03, 1.44 ± 0.02, 2.57 ± 0.04 and 0.18 ± 0.02 g kg-1). Total emissions of CO, CO2, NO2, NO, NOx and SO2 were estimated to be 3.68, 230.51, 0.05, 0.36, 0.60 and 0.03 Gg for rice husk, 33.75, 2140.35, 1.75, 2.91, 6.20 and 0.75 Gg for rice straw, 1.11, 76.28, 0.02, 0.02 and 0.03 Gg for corncobs and 42.12, 3185.53, 1.22, 4.90, 8.74 and 0.61 Gg for bagasse respectively. Rice straw, however, had significantly (p < 0.05) higher potential of gaseous pollutant emission factors. Bagasse had the highest values of total emissions followed by rice straw, rice husk and corncobs. Rice straw and bagasse, on cumulative basis, contributed more than 90% of total emissions of gaseous pollutants. Results reported in this study are important in formulating provincial and regional emission budgets of gaseous pollutants

  18. Characterization of polycyclic aromatic hydrocarbon particulate and gaseous emissions from polystyrene combustion

    SciTech Connect

    Durlak, S.K.; Biswas, P.; Shi, J.; Bernhard, M.J.

    1998-08-01

    The partitioning of polycyclic aromatic hydrocarbons (PAHs) between the particulate and gaseous phases resulting from the combustion of polystyrene was studied. A vertical tubular flow furnace was used to incinerate polystyrene spheres at different combustion temperatures to determine the effect of temperature and polystyrene feed size on the particulate and gaseous emissions and their chemical composition. The furnace reactor exhaust was sampled using real-time instruments (differential mobility particle sizer and/or optical particle counter) to determine the particle size distribution. For chemical composition analyses, the particles were either collected on Teflon filters or split into eight size fractions using a cascade impactor with filter media substrates, while the gaseous products were collected on XAD-2 adsorbent. Gas chromatography/mass spectroscopy was used to identify and quantify the specific PAH species, their partitioning between the gas and particulate phases, and their distribution as a function of emission particle size. The total mass and number of PAH species in both the particulate and gas phases were found to decrease with increasing incineration temperature and decreasing polystyrene feed size, while the mean diameter of the particles increases with increasing incineration temperature and decreasing feed size. In addition, the PAH species in the particulate phase were found to be concentrated in the smaller aerosol sizes.

  19. Direct estimation of diffuse gaseous emissions from coal fires: current methods and future directions

    USGS Publications Warehouse

    Engle, Mark A.; Olea, Ricardo A.; O'Keefe, Jennifer M. K.; Hower, James C.; Geboy, Nicholas J.

    2013-01-01

    Coal fires occur in nature spontaneously, contribute to increases in greenhouse gases, and emit atmospheric toxicants. Increasing interest in quantifying coal fire emissions has resulted in the adaptation and development of specialized approaches and adoption of numerical modeling techniques. Overview of these methods for direct estimation of diffuse gas emissions from coal fires is presented in this paper. Here we take advantage of stochastic Gaussian simulation to interpolate CO2 fluxes measured using a dynamic closed chamber at the Ruth Mullins coal fire in Perry County, Kentucky. This approach allows for preparing a map of diffuse gas emissions, one of the two primary ways that gases emanate from coal fires, and establishing the reliability of the study both locally and for the entire fire. Future research directions include continuous and automated sampling to improve quantification of gaseous coal fire emissions.

  20. 40 CFR Appendix Xvi to Part 86 - Pollutant Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Pollutant Mass Emissions Calculation... Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles Equipped With...-Fueled Vehicle Pollutant Mass Emission Calculation Procedure. (1) For all TLEVs, LEVs, and ULEVs,...

  1. 40 CFR Appendix Xvi to Part 86 - Pollutant Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Pollutant Mass Emissions Calculation... Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles Equipped With...-Fueled Vehicle Pollutant Mass Emission Calculation Procedure. (1) For all TLEVs, LEVs, and ULEVs,...

  2. Particles and gaseous emissions from realistic operation of residential wood pellet heating systems

    NASA Astrophysics Data System (ADS)

    Win, Kaung Myat; Persson, Tomas; Bales, Chris

    2012-11-01

    Gaseous and particulate emissions from six residential wood pellet heating systems are determined at a realistic six day operation sequence. The study aims to investigate the total emissions from a realistic operation of the heating systems including start-up and stop phases. Five combined solar and pellet heating systems and one reference boiler without solar system with an integrated DHW preparation was tested in a laboratory at realistic operation conditions. The investigated emissions comprised carbon monoxide (CO), nitrogen oxide (NO), total organic carbon (TOC) and particulate matter (PM2.5). In this study, the emissions are presented as accumulated total emissions from the whole six days period and the emissions from start-up and stop phases are also presented separately to evaluate the influence of the emissions from these phases on the total emissions. Emission factors of the measured systems from the six day period are between 192 and 547 mg MJ-1 for the CO emissions, between 61 and 95 mg MJ-1 for the NO, between 6 and 45 mg MJ-1 for the TOC, between 31 and 116 mg MJ-1 for the particulate matter and between 2.1 × 1013 and 4 × 1013 for the number of particles. The emissions from the start-up and stop phases are significantly high for the CO (63-95 %) and the TOC (48-93 %). NO and particles emissions are shown to dominate during stationary operation. However, 30-40 % of the particle emissions arise from the start and stop periods. It is also shown that the average emissions of CO, TOC and particles under the realistic annual conditions were higher than the limit values of two eco labels.

  3. Application of electronic nose for industrial odors and gaseous emissions measurement and monitoring--An overview.

    PubMed

    Deshmukh, Sharvari; Bandyopadhyay, Rajib; Bhattacharyya, Nabarun; Pandey, R A; Jana, Arun

    2015-11-01

    The present review evaluates the key modules of the electronic nose, a biomimetic system, with specific examples of applications to industrial emissions monitoring and measurement. Regulations concerning the odor control are becoming very strict, due to ever mounting environmental pollution and its subsequent consequences and it is advantageous to employ real time measurement system. In this perspective, systems like the electronic nose are an improved substitute for assessing the complex industrial emissions over other analytical techniques (odorant concentration measurement) and olfactometry (odor concentration measurement). Compared to tools like gas chromatography, electronic nose systems are easy to develop, are non-destructive and useful for both laboratory and on field purposes. Although there has been immense development of more sensitive and selective sensor arrays and advanced data mining techniques, there have been limited reports on the application of electronic nose for the measurement of industrial emissions. The current study sheds light on the practical applicability of electronic nose for the effective industrial odor and gaseous emissions measurement. The applications categorization is based on gaseous pollutants released from the industries. Calibration and calibration transfer methodologies have been discussed to enhance the applicability of electronic nose system. Further, industrial gas grab sampling technique is reviewed. Lastly, the electronic mucosa system, which has the ability to overcome the flaws of electronic nose system, has been examined. The review ends with the concluding remarks describing the pros and cons of artificial olfaction technique for the industrial applications. PMID:26452830

  4. Particulate and gaseous emissions from manually and automatically fired small scale combustion systems

    NASA Astrophysics Data System (ADS)

    Schmidl, Christoph; Luisser, Markus; Padouvas, Emmanuel; Lasselsberger, Leopold; Rzaca, Magdalena; Ramirez-Santa Cruz, Carlos; Handler, Markus; Peng, Ge; Bauer, Heidi; Puxbaum, Hans

    2011-12-01

    In an extensive wood combustion source test series 2 automatically and 2 manually fired appliances, and 8 fuel types were investigated with respect to their particulate (PM10) and gaseous emissions. Softwood briquettes, beech, oak and spruce logs, wood pellets as well as further biogenic fuels: wood chips, miscanthus (elephant grass) pellets and triticale ("energy crop") pellets were tested. Gaseous emissions were measured continuously while PM10 was sampled with a dilution system and averaged over standard test cycles. Manually fired stoves exhibited highly variable emissions resulting in an uncertainty of 30% for most measured compounds, determined in a series of replicate experiments. Average PM10 emissions from manually fired appliances were around 130 mg m -3 (standard conditions for temperature and pressure (STP), 13%O 2, dry gas), equivalent to 90 mg MJ -1. Wood pellets and chips combustion under full load operation with automatically fired appliances emit almost one order of magnitude less PM10, respectively: 12-21 mg m -3 (STP, 13%O 2, dry gas), or 8-14 mg MJ -1. Around 30% of total particle mass from manually fired systems account for elemental carbon and 30-40% for organic carbon, resulting in carbonaceous fraction content of around 90%. On average around 5% of PM10 emitted by manually fired stoves consisted of levoglucosan while this anhydrous sugar was below detection limit in full- and part load operation of automatically fired systems. Generally, emissions from automated systems were relatively constant for the same fuel type predominantly consisting of inorganic constituents. Emissions are mainly influenced by the mode of operation, start-up, full load or part load for a given fuel type. Surprisingly high emissions were observed for triticale pellets: 184 mg m -3 (125 mg MJ -1,) PM10 and 466 mg m -3 (395 mg MJ -1) NO x, (under full load operation, STP, 13%O 2, dry gas), originating from high chlorine and nitrogen contents of the fuel.

  5. A new statistical approach for establishing high-resolution emission inventory of primary gaseous air pollutants

    NASA Astrophysics Data System (ADS)

    Zhou, Ying; Cheng, Shuiyuan; Chen, Dongsheng; Lang, Jianlei; Zhao, Beibei; Wei, Wei

    2014-09-01

    This paper, which aims at the primary gaseous air pollutants (i.e., SO2, NOx, VOCS and CO), is the third paper in the series papers published in Atmospheric Environment to develop new emission estimation models by the regression method. A group of regression models for various industrial and non-industrial sectors were proposed based on an emission investigation case study of Handan region in northern China. The main data requirements of the regression models for industrial sectors were coal consumption, oil consumption, gaseous fuel consumption and annual industrial output. The data requirements for non-industrial sector emission estimations were the population, the number of resident population households, the vehicle population, the area of construction sites, the forestland area, and the orchard area. The models were then applied to Tangshan region in northern China. The results showed that the developed regression models had relatively satisfactory performance. The modeling errors at the regional level for SO2, NOx, VOCS and CO were -16.5%, -10.6%, -11.8% and -22.6%, respectively. The corresponding modeling errors at the county level were 39.9%, 33.9%, 46.3% and 46.9%, respectively. The models were also applied to other regions in northern China. The results revealed that the new models could develop emission inventories with generally lower error than found in previous emission inventory studies. The developed models had the advantages of only using publicly available statistical information for developing high-accuracy and high-resolution emission inventory, without requiring detailed data investigation which is necessary by conventional “bottom-up” emission inventory development approach.

  6. Gaseous exhaust emissions from a JT8D-109 turbofan engine at simulated cruise flight conditions

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.; Holdeman, J. D.

    1975-01-01

    Gaseous emissions from a JT8D-109 turbofan engine were measured in an altitude facility at four simulated cruise flight conditions: Mach 0.8 at altitudes of 9.1, 10, 7, and 12.2 km and Mach 0.9 at 10.7 km. Engine inlet air temperature was held constant at 283 K for all tests. Emissions measurements were made at nominally 6 cm intervals across the horizontal diameter of the engine exhaust nozzle with a single-point traversing gas sample probe. Measured emissions of decreased with increasing altitude from an emission index of 10.4 to one of 8.3, while carbon monoxide increased with increasing altitude from an emission index of 1.6 to one of 4.4. Unburned hydrocarbon emissions were essentially negligible for all flight conditions. Since the engine inlet air temperatures were not correctly simulated, the NOx emission indices were corrected to true altitude conditions by using correlating parameters for changes in combustor inlet temperature, pressure, and temperature rise. The correction was small at the lowest altitude. At the 10.7 and 12.2 km, Mach 0.8 test conditions the correction decreased the measured values by 1 emission index.

  7. Predicting gaseous emissions from small-scale combustion of agricultural biomass fuels.

    PubMed

    Fournel, S; Marcos, B; Godbout, S; Heitz, M

    2015-03-01

    A prediction model of gaseous emissions (CO, CO2, NOx, SO2 and HCl) from small-scale combustion of agricultural biomass fuels was developed in order to rapidly assess their potential to be burned in accordance to current environmental threshold values. The model was established based on calculation of thermodynamic equilibrium of reactive multicomponent systems using Gibbs free energy minimization. Since this method has been widely used to estimate the composition of the syngas from wood gasification, the model was first validated by comparing its prediction results with those of similar models from the literature. The model was then used to evaluate the main gas emissions from the combustion of four dedicated energy crops (short-rotation willow, reed canary grass, switchgrass and miscanthus) previously burned in a 29-kW boiler. The prediction values revealed good agreement with the experimental results. The model was particularly effective in estimating the influence of harvest season on SO2 emissions. PMID:25543541

  8. Gaseous and particulate emissions from thermal power plants operating on different technologies.

    PubMed

    Athar, Makshoof; Ali, Mahboob; Khan, Misbahul Ain

    2010-07-01

    This paper presents the assessment of gaseous and particulate emissions from thermal power plants operating on different combustion technologies. Four thermal power plants operating on heavy furnace oil were selected for the study, among which three were based on diesel engine technology, while the fourth plant was based on oil-fired steam turbine technology. The stack emissions were monitored for critical air pollutants carbon monoxide, carbon dioxide, oxides of nitrogen, sulfur dioxide, particulate matter, lead, and mercury. The pollutant emissions were measured at optimum load conditions for a period of 6 months with an interval of 1 month. The results of stack emissions were compared with National Environmental Quality Standards of Pakistan and World Bank guidelines for thermal power plants, and few parameters were found higher than the permissible limits of emissions. It was observed that the emissions carbon monoxide, oxides of nitrogen, and particulate matters from diesel engine-based power plants were comparatively higher than the turbine-based power plants. The emissions of sulfur dioxide were high in all the plants, even the plants with different technologies, which was mainly due to high sulfur contents in fuel. PMID:19533397

  9. Probing the gaseous halo of galaxies through non-thermal emission from AGN-driven outflows

    NASA Astrophysics Data System (ADS)

    Wang, Xiawei; Loeb, Abraham

    2015-10-01

    Feedback from outflows driven by active galactic nuclei (AGN) can affect the distribution and properties of the gaseous haloes of galaxies. We study the hydrodynamics and non-thermal emission from the forward outflow shock produced by an AGN-driven outflow. We consider a few possible profiles for the halo gas density, self-consistently constrained by the halo mass, redshift and the disc baryonic concentration of the galaxy. We show that the outflow velocity levels off at ˜ 103 km s- 1 within the scale of the galaxy disc. Typically, the outflow can reach the virial radius around the time when the AGN shuts off. We show that the outflows are energy-driven, consistent with observations and recent theoretical findings. The outflow shock lights up the haloes of massive galaxies across a broad wavelength range. For Milky Way mass haloes, radio observations by the Jansky Very Large Array and the Square Kilometre Array and infrared/optical observations by the James Webb Space Telescope and Hubble Space Telescope can detect the emission signal of angular size ˜8 arcsec from galaxies out to redshift z ˜ 5. Millimetre observations by the Atacama Large Millimeter/submillimeter Array are sensitive to non-thermal emission of angular size ˜18 arcsec from galaxies at redshift z ≲ 1, while X-ray observations by Chandra, XMM-Newton and the Advanced Telescope for High Energy Astrophysics are limited to local galaxies (z ≲ 0.1) with an emission angular size of ˜2 arcmin. Overall, the extended non-thermal emission provides a new way of probing the gaseous haloes of galaxies at high redshifts.

  10. Gaseous Emissions from Light-Duty Vehicles: Moving from NEDC to the New WLTP Test Procedure.

    PubMed

    Marotta, Alessandro; Pavlovic, Jelica; Ciuffo, Biagio; Serra, Simone; Fontaras, Georgios

    2015-07-21

    The Worldwide Harmonized Light Duty Test Procedure (WLTP), recently issued as GTR15 by UNECE-WP29, is designed to check the pollutant emission compliance of Light Duty Vehicles (LDVs) around the world and to establish the reference vehicle fuel consumption and CO2 performance. In the course of the development of WLTP, the Joint Research Center (JRC) of the European Commission has tested gaseous emissions of twenty-one Euro 4-6 gasoline and diesel vehicles, on both the current European type approval test procedure (NEDC) and the progressive versions of the WLTP. The results, which should be regarded just as an initial and qualitative indication of the trends, demonstrated minimal average differences between CO2 emissions over the NEDC and WLTP. On the other hand, CO2 emissions measured at JRC on the NEDC were on average 9% higher than the respective type approval values, therefore suggesting that for the tested vehicles, CO2 emissions over WLTP were almost 10% higher than the respective NEDC type approval values. That difference is likely to increase with application of the full WLTP test procedure. Measured THC emissions from most vehicles stayed below the legal emission limits and in general were lower under the WLTP compared to NEDC. Moving from NEDC to WLTP did not have much impact on NOx from gasoline vehicles and CO from diesel vehicles. On the contrary, NOx from diesel vehicles and CO from low-powered gasoline vehicles were significantly higher over the more dynamic WLTP and in several cases exceeded the emission limits. Results from this study can be considered indicative of emission patterns of modern technology vehicles and useful to both policy makers and vehicle manufacturers in developing future emission policy/technology strategies. PMID:26111353

  11. Emissions factors for gaseous and particulate pollutants from offshore diesel engine vessels in China

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Chen, Y.; Tian, C.; Li, J.; Zhang, G.; Matthias, V.

    2015-09-01

    Shipping emissions have significant influence on atmospheric environment as well as human health, especially in coastal areas and the harbor districts. However, the contribution of shipping emissions on the environment in China still need to be clarified especially based on measurement data, with the large number ownership of vessels and the rapid developments of ports, international trade and shipbuilding industry. Pollutants in the gaseous phase (carbon monoxide, sulfur dioxide, nitrogen oxides, total volatile organic compounds) and particle phase (particulate matter, organic carbon, elemental carbon, sulfates, nitrate, ammonia, metals) in the exhaust from three different diesel engine power offshore vessels in China were measured in this study. Concentrations, fuel-based and power-based emissions factors for various operating modes as well as the impact of engine speed on emissions were determined. Observed concentrations and emissions factors for carbon monoxide, nitrogen oxides, total volatile organic compounds, and particulate matter were higher for the low engine power vessel than for the two higher engine power vessels. Fuel-based average emissions factors for all pollutants except sulfur dioxide in the low engine power engineering vessel were significantly higher than that of the previous studies, while for the two higher engine power vessels, the fuel-based average emissions factors for all pollutants were comparable to the results of the previous studies. The fuel-based average emissions factor for nitrogen oxides for the small engine power vessel was more than twice the International Maritime Organization standard, while those for the other two vessels were below the standard. Emissions factors for all three vessels were significantly different during different operating modes. Organic carbon and elemental carbon were the main components of particulate matter, while water-soluble ions and elements were present in trace amounts. Best-fit engine speeds

  12. Characterization of gaseous pollutant and particulate matter emission rates from a commercial broiler operation part I: Observed trends in emissions

    NASA Astrophysics Data System (ADS)

    Roumeliotis, Taylor S.; Dixon, Brad J.; Van Heyst, Bill J.

    2010-10-01

    This paper characterizes the emission rates of size fractionated particulate matter, inorganic aerosols, acid gases, ammonia and methane measured over four flocks at a commercial broiler chicken facility. Mean emission rates of each pollutant, along with sampling notes, were reported in this paper, the first in a series of two. Sampling notes were needed because inherent gaps in data may bias the mean emission rates. The mean emission rates of PM 10 and PM 2.5 were 5.0 and 0.78 g day -1 [Animal Unit, AU] -1, respectively, while inorganic aerosols mean emission rates ranged from 0.15 to 0.46 g day -1 AU -1 depending on the season. The average total acid gas emission rate was 0.43 g day -1 AU -1 with the greatest contribution from nitrous and nitric acids and little contribution from sulfuric acid (as SO 2). Ammonia emissions were seasonally dependent, with a mean emission rate of 66.0 g day -1 AU -1 in the cooler seasons and 94.5 g day -1 AU -1 during the warmer seasons. Methane emissions were relatively consistent with a mean emission rate of 208 g day -1 AU -1. The diurnal pattern in each pollutant's emission rate was relatively consistent after normalizing the hourly emissions according to each daily mean emission rate. Over the duration of a production cycle, all the measured pollutants' emissions increased proportionally to the total live mass of birds in the house, with the exception of ammonia. Interrelationships between pollutants provide evidence of mutually dependent release mechanisms, which suggests that it may be possible to fill data gaps with minimal data requirements. In the second paper (Roumeliotis, T.S., Dixon, B.J., Van Heyst, B.J. Characterization of gaseous pollutants and particulate matter emission rates from a commercial broiler operation part II: correlated emission rates. Atmospheric Environment, 2010.), regression correlations are developed to estimate daily mean emission rates for data gaps and, using the normalized hourly diurnal

  13. Gaseous emissions from sewage sludge combustion in a moving bed combustor.

    PubMed

    Batistella, Luciane; Silva, Valdemar; Suzin, Renato C; Virmond, Elaine; Althoff, Chrtistine A; Moreira, Regina F P M; José, Humberto J

    2015-12-01

    Substantial increase in sewage sludge generation in recent years requires suitable destination for this residue. This study evaluated the gaseous emissions generated during combustion of an aerobic sewage sludge in a pilot scale moving bed reactor. To utilize the heat generated during combustion, the exhaust gas was applied to the raw sludge drying process. The gaseous emissions were analyzed both after the combustion and drying steps. The results of the sewage sludge characterization showed the energy potential of this residue (LHV equal to 14.5 MJ kg(-1), db) and low concentration of metals, polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The concentration of CO, NOx, BTEX (benzene, toluene, ethylbenzene and xylenes) emitted from the sludge combustion process were lower than the legal limits. The overall sludge combustion and drying process showed low emissions of PCDD/PCDF (0.42 ng I-TEQ N m(-3)). BTEX and PAH emissions were not detected. Even with the high nitrogen concentration in the raw feed (5.88% db), the sludge combustion process presented NOx emissions below the legal limit, which results from the combination of appropriate feed rate (A/F ratio), excess air, and mainly the low temperature kept inside the combustion chamber. It was found that the level of CO emissions from the overall sludge process depends on the dryer operating conditions, such as the oxygen content and the drying temperature, which have to be controlled throughout the process in order to achieve low CO levels. The aerobic sewage sludge combustion process generated high SO2 concentration due to the high sulfur content (0.67 wt%, db) and low calcium concentration (22.99 g kg(-1)) found in the sludge. The high concentration of SO2 in the flue gas (4776.77 mg N m(-3)) is the main factor inhibiting PCDD/PCDF formation. Further changes are needed in the pilot plant scheme to reduce SO2 and particulate matter emissions

  14. Effects of phosphogypsum and superphosphate on compost maturity and gaseous emissions during kitchen waste composting.

    PubMed

    Yang, Fan; Li, Guoxue; Shi, Hong; Wang, Yiming

    2015-02-01

    This study investigated the effects of phosphogypsum and superphosphate on the maturity and gaseous emissions of composting kitchen waste. Two amended compost treatments were conducted using phosphogypsum and superphosphate as additives with the addition of 10% of initial raw materials (dry weight). A control treatment was also studied. The treatments were conducted under aerobic conditions in 60-L reactors for 35 days. Maturity indexes were determined, and continuous measurements of CH4, N2O, and NH3 were taken. Phosphogypsum and superphosphate had no negative effects on compost maturity, although superphosphate inhibited the temperature rise in the first few days. The addition of phosphogypsum and superphosphate drastically reduced CH4 emissions (by 85.8% and 80.5%, respectively) and decreased NH3 emissions (by 23.5% and 18.9%, respectively). However, a slight increase in N2O emissions (by 3.2% and 14.8%, respectively) was observed. Composting with phosphogypsum and superphosphate reduced total greenhouse gas emissions by 17.4% and 7.3% respectively. PMID:25481697

  15. On-road vehicle particulate matter and gaseous emission distributions in Las Vegas, Nevada, compared with other areas.

    PubMed

    Mazzoleni, Claudio; Kuhns, Hampden D; Moosmüller, Hans; Keislar, Robert E; Barber, Peter W; Robinson, Norman F; Watson, John G; Nikolic, Djordje

    2004-06-01

    During the spring and summer of 2000, 2001, and 2002, gaseous and particulate matter (PM) fuel-based emission factors for approximately 150,000 low-tailpipe, individual vehicles in the Las Vegas, NV, area were measured via on-road remote sensing. For the gaseous pollutants (carbon monoxide, hydrocarbons, and nitrogen oxide), a commercial vehicle emissions remote sensing system (VERSS) was used. The PM emissions were determined using a Lidar-based VERSS. Emission distributions and their shapes were analyzed and compared with previous studies. The large skewness of the distributions is evident for both gaseous pollutants and PM and has important implications for emission reduction policies, because the majority of emissions are attributed to a small fraction of vehicles. Results of this Las Vegas study and studies at other geographical locations were compared. The gaseous pollutants were found to be close to those measured by VERSS in other U.S. cities. The PM emission factors for spark ignition and diesel vehicles are in the range of previous tunnel and dynamometer studies. PMID:15242151

  16. Effects of phosphogypsum and superphosphate on compost maturity and gaseous emissions during kitchen waste composting

    SciTech Connect

    Yang, Fan; Li, Guoxue; Shi, Hong; Wang, Yiming

    2015-02-15

    Highlights: • Effect of phosphogypsum and superphosphate on composting gas emissions was studied. • The reduction mechanisms of composting gas were clarified in this study. • No negative effect was caused on maturity with phosphogypsum and superphosphate. • CH{sub 4} and NH{sub 3} emission was decreased with phosphogypsum and superphosphate addition. • GHG decreased by 17.4% and 7.3% with phosphogypsum and superphosphate addition. - Abstract: This study investigated the effects of phosphogypsum and superphosphate on the maturity and gaseous emissions of composting kitchen waste. Two amended compost treatments were conducted using phosphogypsum and superphosphate as additives with the addition of 10% of initial raw materials (dry weight). A control treatment was also studied. The treatments were conducted under aerobic conditions in 60-L reactors for 35 days. Maturity indexes were determined, and continuous measurements of CH{sub 4}, N{sub 2}O, and NH{sub 3} were taken. Phosphogypsum and superphosphate had no negative effects on compost maturity, although superphosphate inhibited the temperature rise in the first few days. The addition of phosphogypsum and superphosphate drastically reduced CH{sub 4} emissions (by 85.8% and 80.5%, respectively) and decreased NH{sub 3} emissions (by 23.5% and 18.9%, respectively). However, a slight increase in N{sub 2}O emissions (by 3.2% and 14.8%, respectively) was observed. Composting with phosphogypsum and superphosphate reduced total greenhouse gas emissions by 17.4% and 7.3% respectively.

  17. Gaseous mercury emissions from soil following forest loss and land use changes: Field experiments in the United States and Brazil

    NASA Astrophysics Data System (ADS)

    Carpi, Anthony; Fostier, Anne H.; Orta, Olivia R.; dos Santos, Jose Carlos; Gittings, Michael

    2014-10-01

    Forest ecosystems are a sink of atmospheric mercury, trapping the metal in the canopy, and storing it in the forest floor after litter fall. Fire liberates a portion of this mercury; however, little is known about the long-term release of mercury post deforestation. We conducted two large-scale experiments to study this phenomenon. In upstate New York, gaseous mercury emissions from soil were monitored continually using a Teflon dynamic surface flux chamber for two-weeks before and after cutting of the canopy on the edge of a deciduous forest. In Brazil, gaseous mercury emissions from soil were monitored in an intact Ombrophilous Open forest and an adjacent field site both before and after the field site was cleared by burning. In the intact forest, gaseous mercury emissions from soil averaged -0.73 ± 1.84 ng m-2 h-1 (24-h monitoring) at the New York site, and 0.33 ± 0.09 ng m-2 h-1 (daytime-only) at the Brazil site. After deforestation, gaseous mercury emissions from soil averaged 9.13 ± 2.08 ng m-2 h-1 in New York and 21.2 ± 0.35 ng m-2 h-1 at the Brazil site prior to burning. Gaseous mercury emissions averaged 74.9 ± 0.73 ng m-2 h-1 after burning of the cut forest in Brazil. Extrapolating our data, measured over several weeks to months, to a full year period, deforested soil is estimated to release an additional 2.30 g ha-1 yr-1 of gaseous mercury to the atmosphere in the Brazilian experiment and 0.41 g ha-1 yr-1 in the New York experiment. In Brazil, this represents an additional 50% of the mercury load released during the fire itself.

  18. Particulate and gaseous emissions from the combustion of different biofuels in a pellet stove

    NASA Astrophysics Data System (ADS)

    Vicente, E. D.; Duarte, M. A.; Tarelho, L. A. C.; Nunes, T. F.; Amato, F.; Querol, X.; Colombi, C.; Gianelle, V.; Alves, C. A.

    2015-11-01

    Seven fuels (four types of wood pellets and three agro-fuels) were tested in an automatic pellet stove (9.5 kWth) in order to determine emission factors (EFs) of gaseous compounds, such as carbon monoxide (CO), methane (CH4), formaldehyde (HCHO), and total organic carbon (TOC). Particulate matter (PM10) EFs and the corresponding chemical compositions for each fuel were also obtained. Samples were analysed for organic carbon (OC) and elemental carbon (EC), anhydrosugars and 57 chemical elements. The fuel type clearly affected the gaseous and particulate emissions. The CO EFs ranged from 90.9 ± 19.3 (pellets type IV) to 1480 ± 125 mg MJ-1 (olive pit). Wood pellets presented the lowest TOC emission factor among all fuels. HCHO and CH4 EFs ranged from 1.01 ± 0.11 to 36.9 ± 6.3 mg MJ-1 and from 0.23 ± 0.03 to 28.7 ± 5.7 mg MJ-1, respectively. Olive pit was the fuel with highest emissions of these volatile organic compounds. The PM10 EFs ranged from 26.6 ± 3.14 to 169 ± 23.6 mg MJ-1. The lowest PM10 emission factor was found for wood pellets type I (fuel with low ash content), whist the highest was observed during the combustion of an agricultural fuel (olive pit). The OC content of PM10 ranged from 8 wt.% (pellets type III) to 29 wt.% (olive pit). Variable EC particle mass fractions, ranging from 3 wt.% (olive pit) to 47 wt.% (shell of pine nuts), were also observed. The carbonaceous content of particulate matter was lower than that reported previously during the combustion of several wood fuels in traditional woodstoves and fireplaces. Levoglucosan was the most abundant anhydrosugar, comprising 0.02-3.03 wt.% of the particle mass. Mannosan and galactosan were not detected in almost all samples. Elements represented 11-32 wt.% of the PM10 mass emitted, showing great variability depending on the type of biofuel used.

  19. Odorous gaseous emissions as influence by process condition for the forced aeration composting of pig slaughterhouse sludge

    SciTech Connect

    Blazy, V.; Guardia, A. de; Benoist, J.C; Daumoin, M.; Lemasle, M.; Wolbert, D.; Barrington, S.

    2014-07-15

    Highlights: • The gaseous emissions produced by various composting process conditions were characterized and quantified. • Nine compounds were potentially odorous: TMA, NH{sub 3}, 2-pentanone, 1-propanol-2-methyl, acetophenone and sulphur forms. • The tested composting process conditions reduced odour emissions by a factor of 5–10. • A reduction of 10{sup 5} to 10{sup 6} is required to reach an odour threshold limit at peak event emissions. • Both aeration rate and bulking agent had the most impact on reducing odour emissions. - Abstract: Compost sustainability requires a better control of its gaseous emissions responsible for several impacts including odours. Indeed, composting odours have stopped the operation of many platforms and prevented the installation of others. Accordingly, present technologies collecting and treating gases emitted from composting are not satisfactory and alternative solutions must be found. Thus, the aim of this paper was to study the influence of composting process conditions on gaseous emissions. Pig slaughterhouse sludge mixed with wood chips was composted under forced aeration in 300 L laboratory reactors. The process conditions studied were: aeration rate of 1.68, 4.03, 6.22, 9.80 and 13.44 L/h/kg of wet sludge; incorporation ratio of 0.55, 0.83 and 1.1 (kg of wet wood chips/kg of wet sludge), and; bulking agent particles size of <10, 10 < 20 and 20 < 30 mm. Out-going gases were sampled every 2 days and their composition was analysed using gas chromatography coupled with mass spectrometry (GC–MS). Fifty-nine compounds were identified and quantified. Dividing the cumulated mass production over 30 days of composting, by odour threshold, 9 compounds were identified as main potential odour contributors: hydrogen sulphide, trimethylamine, ammonia, 2-pentanone, 1-propanol-2-methyl, dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide and acetophenone. Five gaseous compounds were correlated with both aeration rate and

  20. Environmental effects of increased coal utilization: ecological effects of gaseous emissions from coal combustion.

    PubMed Central

    Glass, N R

    1979-01-01

    This report is limited to an evaluation of the ecological and environmental effects of gaseous emissions and aerosols of various types which result from coal combustion. It deals with NOx, SOx, fine particulate, photochemical oxidant and acid precipitation as these pollutants affect natural and managed resources and ecosystems. Also, synergistic effects involving two or more pollutants are evaluated as well as ecosystem level effects of gaseous pollutants. There is a brief summary of the effects on materials and atmospheric visibility of increased coal combustion. The economic implications of ecological effects are identified to the extent they can be determined within acceptable limits. Aquatic and terrestrial effects are distinguished where the pollutants in question are clearly problems in both media. At present, acid precipitation is most abundant in the north central and northeastern states. Total SOx and NOx emissions are projected to remain high in these regions while increasing relatively more in the western than in the eastern regions of the country. A variety of ecological processes are affected and altered by air pollution. Such processes include community succession and retrogression, nutrient biogeochemical cycling, photosynthetic activity, primary and secondary productivity, species diversity and community stability. Estimates of the non health-related cost of air pollutants range from several hundred million dollars to $1.7 billion dollars per year. In general, these estimates include only those relatively easily measured considerations such as the known losses to cultivate crops from acute air pollution episodes or the cost of frequent repainting required as a result of air pollution. No substantial nationwide estimates of losses to forest productivity, natural ecosystem productivity which is tapped by domestic grazing animals and wildlife, and other significant dollar losses are available. PMID:44247

  1. Impacts of a Nanosized Ceria Additive on Diesel Engine Emissions of Particulate and Gaseous Pollutants

    PubMed Central

    Zhang, Junfeng; Nazarenko, Yevgen; Zhang, Lin; Calderon, Leonardo; Lee, Ki-Bum; Garfunkel, Eric; Schwander, Stephan; Tetley, Teresa D.; Chung, Kian Fan; Porter, Alexandra E.; Ryan, Mary; Kipen, Howard; Lioy, Paul J.; Mainelis, Gediminas

    2014-01-01

    Fuel additives incorporating nanosized ceria have been increasingly used in diesel engines as combustion promoters. However, few studies have assessed the impact of these nanotechnology-based additives on pollutant emissions. Here, we systematically compare emission rates of particulate and gaseous pollutants from a single-cylinder, four-cycle diesel engine using fuel mixes containing nanoceria of varying concentrations. The test fuels were made by adding different amounts of a commercial fuel additive Envirox into an ultralow-sulfur diesel fuel at 0 (base fuel), 0.1-, 1-, and 10-fold the manufacturer-recommended concentration of 0.5 mL Envirox per liter of fuel. The addition of Envirox resulted in ceria-concentration-dependent emission reductions of CO2, CO, total particulate mass, formaldehyde, acetaldehyde, acrolein, and several polycyclic aromatic hydrocarbons. These reductions at the manufacturer-recommended doping concentration, however, were accompanied by a substantial increase of certain other air pollutants, specifically the number of ultrafine particles (+32%), NOx (+9.3%), and the particle-phase benzo[a]pyrene toxic equivalence quotient (+35%). Increasing fuel ceria concentrations also led to decreases in the size of emitted particles. Given health concerns related to ultrafine particles and NOx, our findings call for additional studies to further evaluate health risks associated with the use of nanoceria additives in various engines under various operating conditions. PMID:24144266

  2. Effects of aeration rate on maturity and gaseous emissions during sewage sludge composting.

    PubMed

    Yuan, Jing; Chadwick, David; Zhang, Difang; Li, Guoxue; Chen, Shili; Luo, Wenhai; Du, Longlong; He, Shengzhou; Peng, Shengping

    2016-10-01

    This study investigated effects of aeration rate (AR) on maturity and gaseous emissions during sewage sludge composting, sewage sludge and corn stalks as the bulking agent were co-composted at different ARs (0.1, 0.2, 0.3L·kg(-1) dry matter (DM)·min(-1)). The thermophilic phase for the low and moderate AR treatments was able meet sanitation requirements, but too short to meet sanitation requirements in the high AR treatment. The high AR treatment was significantly different from the other treatments, and had the lowest electrical conductivity and highest E4/E6(absorbance ratio of wavelength 465 and 665nm). The AR influences the nitrogen variations; high AR compost had the highest NH4(+)-N content and lowest NOx(-)-N content. The AR was the main factor influencing compost stability, but the AR had little impact on pH and the germination index. The moderate AR treatment had the highest NH3 emissions during composting, while the low AR treatment had the highest CH4 and N2O emissions. Based on our comprehensive investigation, the recommended AR for sludge composting is 0.2L·kg(-1) DM·min(-1). PMID:27425860

  3. Impacts of a nanosized ceria additive on diesel engine emissions of particulate and gaseous pollutants.

    PubMed

    Zhang, Junfeng; Nazarenko, Yevgen; Zhang, Lin; Calderon, Leonardo; Lee, Ki-Bum; Garfunkel, Eric; Schwander, Stephan; Tetley, Teresa D; Chung, Kian Fan; Porter, Alexandra E; Ryan, Mary; Kipen, Howard; Lioy, Paul J; Mainelis, Gediminas

    2013-11-19

    Fuel additives incorporating nanosized ceria have been increasingly used in diesel engines as combustion promoters. However, few studies have assessed the impact of these nanotechnology-based additives on pollutant emissions. Here, we systematically compare emission rates of particulate and gaseous pollutants from a single-cylinder, four-cycle diesel engine using fuel mixes containing nanoceria of varying concentrations. The test fuels were made by adding different amounts of a commercial fuel additive Envirox into an ultralow-sulfur diesel fuel at 0 (base fuel), 0.1-, 1-, and 10-fold the manufacturer-recommended concentration of 0.5 mL Envirox per liter of fuel. The addition of Envirox resulted in ceria-concentration-dependent emission reductions of CO2, CO, total particulate mass, formaldehyde, acetaldehyde, acrolein, and several polycyclic aromatic hydrocarbons. These reductions at the manufacturer-recommended doping concentration, however, were accompanied by a substantial increase of certain other air pollutants, specifically the number of ultrafine particles (+32%), NO(x) (+9.3%), and the particle-phase benzo[a]pyrene toxic equivalence quotient (+35%). Increasing fuel ceria concentrations also led to decreases in the size of emitted particles. Given health concerns related to ultrafine particles and NO(x), our findings call for additional studies to further evaluate health risks associated with the use of nanoceria additives in various engines under various operating conditions. PMID:24144266

  4. Gaseous contaminant emissions as affected by burning scrap tires in cement manufacturing.

    PubMed

    Carrasco, F; Bredin, N; Heitz, M

    2002-01-01

    We studied the environmental impact (gaseous emissions) of using scrap tires as a fuel substitute at a cement plant that produces one million tons of cement per year. Using a combination of tires and coal as opposed to only coal caused variations in the pollutant emission rate. The study recorded a 37% increase in the rate of emission for CO, a 24% increase for SO2, an 11% decrease for NOx, and a 48% increase for HCl when tires were included. The rate of emission for metals increased 61% for Fe, 33% for Al, 487% for Zn, 127% for Pb, 339% for Cr, 100% for Mn, and 74% for Cu, and decreased 22% for Hg. On the other hand, the emission rate of organic compounds dropped by 14% for polycyclic aromatic hydrocarbons, 8% in naphthalene, 37% in chlorobenzene, and 45% in dioxins and furans. We used a Gaussian model of atmospheric dispersion to calculate the average pollutant concentration (1-h, 24-h, and annual concentrations) in the ambient air at ground level with the help of the ISC-ST2 software program developed by the USEPA. When tires were used, we observed (i) a 12 to 24% increase in particulate matter, this range considering the concentration variation depending on the average used (1-h, 24-h, and annual basis), 31 to 52% in CO, 22 to 34% in SO2, 39 to 52% in HCl, 12 to 27% in Fe, -3 to 8% in Al, 30 to 37% in Zn, and 270 to 885% in Pb; (ii) a decrease of 8 to 13% in NOx, 9 to 13% in polycyclic aromatic hydrocarbons, 6 to 7% in naphthalene, 32 to 39% in chlorobenzene, and 32 to 45% in dioxins and furans. The results obtained showed that the maximum ground-level concentrations were well within the environmental standards (for operation with only coal as well as for operation with a combination of coal and tires). PMID:12371165

  5. A PEMS study of the emissions of gaseous pollutants and ultrafine particles from gasoline- and diesel-fueled vehicles

    NASA Astrophysics Data System (ADS)

    Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Feng, Qian; Chen, Yiran; Chen, Changhong; Tan, Piqiang; Yao, Di

    2013-10-01

    On-road emission measurements of gasoline- and diesel-fueled vehicles were conducted by a portable emission measurement system (PEMS) in Shanghai, China. Horiba OBS 2200 and TSI EEPS 3090 were employed to detect gaseous and ultrafine particle emissions during the tests. The driving-based emission factors of gaseous pollutants and particle mass and number were obtained on various road types. The average NOx emission factors of the diesel bus, diesel car, and gasoline car were 8.86, 0.68, and 0.17 g km-1, all of which were in excess of their emission limits. The particle number emission factors were 7.06 × 1014, 6.08 × 1014, and 1.57 × 1014 km-1, generally higher than the results for similar vehicle types reported in the previous studies. The size distributions of the particles emitted from the diesel vehicles were mainly concentrated in the accumulation mode, while those emitted from the gasoline car were mainly distributed in the nucleation mode. Both gaseous and particle emission rates exhibit significant correlations with the change in vehicle speed and power demand. The lowest emission rates for each vehicle type were produced during idling. The highest emission rates for each vehicle type were generally found in high-VSP bins. The particle number emission rates of the gasoline car show the strongest growth trend with increasing VSP and speed. The particle number emission for the gasoline car increased by 3 orders of magnitude from idling to the highest VSP and driving speed conditions. High engine power caused by aggressive driving or heavy loads is the main contributor to high emissions for these vehicles in real-world situations.

  6. VALIDATION AND IMPROVEMENT OF EPA (ENVIRONMENTAL PROTECTION AGENCY) REFERENCE METHOD 25 - DETERMINATION OF GASEOUS NONMETHANE ORGANIC EMISSIONS AS CARBON

    EPA Science Inventory

    The U.S. Environmental Protection Agency Reference Method 25 measures the total gaseous nonmethane organics as carbon in source emissions. Both laboratory and field studies were conducted to evaluate this method. Tested were the effectiveness of a commercial nonmethane organic an...

  7. Gaseous ammonia in the urban area of Rome, Italy and its relationship with traffic emissions

    NASA Astrophysics Data System (ADS)

    Perrino, C.; Catrambone, M.; Di Menno Di Bucchianico, A.; Allegrini, I.

    The atmospheric concentration of gaseous ammonia has been measured during selected field campaigns from the spring of 2001 to the spring of 2002 in the urban area of Rome, at many traffic sites and at an urban background site. The concentration level at the traffic sites was in all cases about five times the background level and always much higher than the concentration in a rural near-city area. The time trend of ammonia is well correlated with the trend of a primary low-reactivity pollutant such as carbon monoxide. The concentration values of both pollutants depend on the intensity of traffic emission and on the atmospheric mixing in the boundary layer. Ammonia concentration is also dependent on the air temperature. A close link between NH 3 and CO air values has been confirmed at all the measurement stations of the Air Quality Network of Rome. These results indicate that the emissions from petrol-engine vehicles equipped with catalytic converters can be an important source of ammonia in urban areas. The implications of these findings for the chemistry of the urban atmosphere need to be carefully considered.

  8. Theoretical evaluation of a method for locating gaseous emission hot spots.

    PubMed

    Hashmonay, Ram A

    2008-08-01

    This paper describes and theoretically evaluates a recently developed method that provides a unique methodology for mapping gaseous emissions from non-point pollutant sources. The horizontal radial plume mapping (HRPM) methodology uses an open-path, path-integrated optical remote sensing (PI-ORS) system in a horizontal plane to directly identify emission hot spots. The radial plume mapping methodology has been well developed, evaluated, and demonstrated. In this paper, the theoretical basis of the HRPM method is explained in the context of the method's reliability and robustness to reconstruct spatially resolved plume maps. Calculation of the condition number of the inversion's kernel matrix showed that this method has minimal error magnification (EM) when the beam geometry is optimized. Minimizing the condition number provides a tool for such optimization of the beam geometry because it indicates minimized EM. Using methane concentration data collected from a landfill with a tunable diode laser absorption spectroscopy (TDLAS) system, it is demonstrated that EM is minimal because the averaged plume map of many reconstructed plume maps is very similar to a plume map generated by the averaged concentration data. It is also shown in the analysis of this dataset that the reconstructions of plume maps are unique for the optimized HRPM beam geometry and independent of the actual algorithm applied. PMID:18720659

  9. Uncontrolled combustion of shredded tires in a landfill - Part 1: Characterization of gaseous and particulate emissions

    NASA Astrophysics Data System (ADS)

    Downard, Jared; Singh, Ashish; Bullard, Robert; Jayarathne, Thilina; Rathnayake, Chathurika M.; Simmons, Donald L.; Wels, Brian R.; Spak, Scott N.; Peters, Thomas; Beardsley, Douglas; Stanier, Charles O.; Stone, Elizabeth A.

    2015-03-01

    In summer 2012, a landfill liner comprising an estimated 1.3 million shredded tires burned in Iowa City, Iowa. During the fire, continuous monitoring and laboratory measurements were used to characterize the gaseous and particulate emissions and to provide new insights into the qualitative nature of the smoke and the quantity of pollutants emitted. Significant enrichments in ambient concentrations of CO, CO2, SO2, particle number (PN), fine particulate (PM2.5) mass, elemental carbon (EC), and polycyclic aromatic hydrocarbons (PAH) were observed. For the first time, PM2.5 from tire combustion was shown to contain PAH with nitrogen heteroatoms (a.k.a. azaarenes) and picene, a compound previously suggested to be unique to coal-burning. Despite prior laboratory studies' findings, metals used in manufacturing tires (i.e. Zn, Pb, Fe) were not detected in coarse particulate matter (PM10) at a distance of 4.2 km downwind. Ambient measurements were used to derive the first in situ fuel-based emission factors (EF) for the uncontrolled open burning of tires, revealing substantial emissions of SO2 (7.1 g kg-1), particle number (3.5 × 1016 kg-1), PM2.5 (5.3 g kg-1), EC (2.37 g kg-1), and 19 individual PAH (totaling 56 mg kg-1). A large degree of variability was observed in day-to-day EF, reflecting a range of flaming and smoldering conditions of the large-scale fire, for which the modified combustion efficiency ranged from 0.85 to 0.98. Recommendations for future research on this under-characterized source are also provided.

  10. Emission factors for gaseous and particulate pollutants from offshore diesel engine vessels in China

    NASA Astrophysics Data System (ADS)

    Zhang, Fan; Chen, Yingjun; Tian, Chongguo; Lou, Diming; Li, Jun; Zhang, Gan; Matthias, Volker

    2016-05-01

    Shipping emissions have significant influence on atmospheric environment as well as human health, especially in coastal areas and the harbour districts. However, the contribution of shipping emissions on the environment in China still need to be clarified especially based on measurement data, with the large number ownership of vessels and the rapid developments of ports, international trade and shipbuilding industry. Pollutants in the gaseous phase (carbon monoxide, sulfur dioxide, nitrogen oxides, total volatile organic compounds) and particle phase (particulate matter, organic carbon, elemental carbon, sulfates, nitrate, ammonia, metals) in the exhaust from three different diesel-engine-powered offshore vessels in China (350, 600 and 1600 kW) were measured in this study. Concentrations, fuel-based and power-based emission factors for various operating modes as well as the impact of engine speed on emissions were determined. Observed concentrations and emission factors for carbon monoxide, nitrogen oxides, total volatile organic compounds, and particulate matter were higher for the low-engine-power vessel (HH) than for the two higher-engine-power vessels (XYH and DFH); for instance, HH had NOx EF (emission factor) of 25.8 g kWh-1 compared to 7.14 and 6.97 g kWh-1 of DFH, and XYH, and PM EF of 2.09 g kWh-1 compared to 0.14 and 0.04 g kWh-1 of DFH, and XYH. Average emission factors for all pollutants except sulfur dioxide in the low-engine-power engineering vessel (HH) were significantly higher than that of the previous studies (such as 30.2 g kg-1 fuel of CO EF compared to 2.17 to 19.5 g kg-1 fuel in previous studies, 115 g kg-1 fuel of NOx EF compared to 22.3 to 87 g kg-1 fuel in previous studies and 9.40 g kg-1 fuel of PM EF compared to 1.2 to 7.6 g kg-1 fuel in previous studies), while for the two higher-engine-power vessels (DFH and XYH), most of the average emission factors for pollutants were comparable to the results of the previous studies, engine type was

  11. Size-segregated particulate matter and gaseous emissions from motor vehicles in a road tunnel

    NASA Astrophysics Data System (ADS)

    Alves, Célia A.; Gomes, Joana; Nunes, Teresa; Duarte, Márcio; Calvo, Ana; Custódio, Danilo; Pio, Casimiro; Karanasiou, Angeliki; Querol, Xavier

    2015-02-01

    In order to address road traffic emissions, studies need to be performed under realistic driving conditions where the input from other sources is minimised. Measurements in traffic tunnels have been used for quantifying emissions, but so far no study has established emission factors (EFs) for Southern Europe. To fill this gap, a sampling campaign was carried out for one week in the Liberdade Avenue tunnel (Braga, Portugal). The campaign included the monitoring of gaseous pollutants (CO2, CO, NOx) and suspended particulate matter (PM) at two sites, one in the tunnel and another in an urban background location. Organic and elemental carbon (OC and EC) in size-segregated particles (PM0.5, PM0.5-1, PM1-2.5 and PM2.5-10) were determined by a thermal-optical system, whereas major and trace elements were analysed by ICP-MS and ICP-AES. PM0.5 accounted for 56% of the PM10 mass, while PM2.5-10 represented only 12%. The carbonaceous fraction was concentrated in PM0.5, encompassing 88% of the EC and 67% of the OC present in PM10. Elements attributable to non-exhaust emissions could be divided into two groups. Fe, Ba, Cu, Sb, Sn and Zn, from tyre and brake wear, were more abundant in particles between 1 and 2 μm. Ca, Al, K, Sr and Ti, associated with soil resuspension, were mainly present in particles > 2 μm. The average EFs of CO, CO2 and NOx were 212, 4.02 and 1.22 g veh- 1 km- 1, respectively, while values of 152 mg PM10 veh- 1 km- 1 and 133 mg PM2.5 veh- 1 km- 1 were obtained for the particles. OC and EC emission factor was 39 mg veh- 1 km- 1 for PM10. The corresponding OC and EC values for PM2.5 were 34 and 38 mg veh- 1 km- 1. The EFs are slightly lower than those found for other tunnels, but within the ranges presented by the EMEP/EEA inventory.

  12. Gaseous emissions from the combustion of a waste mixture containing a high concentration of N{sub 2}O

    SciTech Connect

    Dong Changqing Yang Yongping; Zhang Junjiao; Lu Xuefeng

    2009-01-15

    This paper is focused on reducing the emissions from the combustion of a waste mixture containing a high concentration of N{sub 2}O. A rate model and an equilibrium model were used to predict gaseous emissions from the combustion of the mixture. The influences of temperature and methane were considered, and the experimental research was carried out in a tabular reactor and a pilot combustion furnace. The results showed that for the waste mixture, the combustion temperature should be in the range of 950-1100 deg. C and the gas residence time should be 2 s or higher to reduce emissions.

  13. Incineration of different types of medical wastes: emission factors for gaseous emissions

    NASA Astrophysics Data System (ADS)

    Alvim-Ferraz, M. C. M.; Afonso, S. A. V.

    Previous research works showed that to protect public health, the hospital incinerators should be provided with air pollution control devices. As most hospital incinerators do not possess such equipment, efficient methodologies should be developed to evaluate the safety of incineration procedure. Emission factors (EF) can be used for an easy estimation of legal parameters. Nevertheless, the actual knowledge is yet very scarce, mainly because EF previously published do not include enough information about the incinerated waste composition, besides considering many different waste classifications. This paper reports the first EF estimated for CO, SO 2, NO x and HCl, associated to the incineration of medical waste, segregated in different types according to the classification of the Portuguese legislation. The results showed that those EF are strongly influenced by incinerated waste composition, directly affected by incinerated waste type, waste classification, segregation practice and management methodology. The correspondence between different waste classifications was analysed comparing the estimated EF with the sole results previously published for specific waste types, being observed that the correspondence is not always possible. The legal limit for pollutant concentrations could be obeyed for NO x, but concentrations were higher than the limit for CO (11-24 times), SO 2 (2-5 times), and HCl (9-200 times), confirming that air pollution control devices must be used to protect human health. The small heating value of medical wastes with compulsory incineration implied the requirement of a bigger amount of auxiliary fuel for their incineration, which affects the emitted amounts of CO, NO x and SO 2 (28, 20 and practically 100% of the respective values were related with fuel combustion). Nevertheless, the incineration of those wastes lead to the smallest amount of emitted pollutants, the emitted amount of SO 2 and NO x reducing to 93% and the emitted amount of CO

  14. Unregulated gaseous exhaust emission from modern ethanol fuelled light duty vehicles in cold ambient condition

    NASA Astrophysics Data System (ADS)

    Clairotte, M.; Adam, T. W.; Zardini, A. A.; Astorga, C.

    2011-12-01

    According to Directive 2003/30/EC and 2009/28/EC of the European Parliament and the Council, Member States should promote the use of biofuel. Consequently, all petrol and diesel used for transport purpose available on the market since the 1st of January 2011 must contain a reference value of 5.75% of renewable energy. Ethanol in gasoline could be a promising alternative to comply with this objective, and is actually available in higher proportion in Sweden and Brazil. In addition to a lower dependence on fossil fuel, it is well established that ethanol contributes to reduce air pollutant emissions during combustion (CO, THC), and presents a beneficial effect on the greenhouse gas emissions. However, these statements rely on numerous chassis dynamometer emission studies performed in warm condition (22°C), and very few emission data are available at cold ambient condition encountered in winter, particularly in the north of Europe. In this present study, the effects of ethanol (E75-E85) versus gasoline (E5) have been investigated at cold ambient temperature (-7°C). Experiments have been carried out in a chassis dynamometer at the Vehicle Emission Laboratory (VELA) of the European Commission's Joint Research Centre (JRC - Ispra, Italy). Emissions of modern passenger cars complying with the latest European standard (Euro4 and Euro5a) were tracked over the New European Driving Cycle (NEDC). Unregulated gaseous compounds like greenhouse gases (carbon dioxide, methane, nitrous oxide), and air quality related compounds (ammonia, formaldehyde, acetaldehyde) were monitored by an online Fourier Transformed Infra-Red spectrometer with 1 Hz acquisition frequency. In addition, a number of ozone precursors (carbonyls and volatile organic hydrocarbons) were collected in order to assess the ozone formation potential (OFP) of the exhaust. Results showed higher unregulated emissions at -7°C, regardless of the ethanol content in the fuel blend. Most of the emissions occurred during

  15. 40 CFR 86.137-90 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-90 Dynamometer test run, gaseous... first period (505 seconds) is run. (2) Petroleum-fueled and methanol-fueled diesel vehicles. The...

  16. 40 CFR 86.137-90 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-90 Dynamometer test run, gaseous... first period (505 seconds) is run. (2) Petroleum-fueled and methanol-fueled diesel vehicles. The...

  17. 40 CFR 86.137-94 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-94 Dynamometer test run, gaseous... statement “ .” (a) General. The dynamometer run consists of two tests, a cold start test, after a minimum...

  18. 40 CFR 86.137-94 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-94 Dynamometer test run, gaseous... statement “ .” (a) General. The dynamometer run consists of two tests, a cold start test, after a minimum...

  19. 40 CFR 86.137-94 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-94 Dynamometer test run, gaseous... statement “ .” (a) General. The dynamometer run consists of two tests, a cold start test, after a minimum...

  20. 40 CFR 86.137-94 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-94 Dynamometer test run, gaseous... statement “ .” (a) General. The dynamometer run consists of two tests, a cold start test, after a minimum...

  1. 40 CFR 86.137-90 - Dynamometer test run, gaseous and particulate emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Dynamometer test run, gaseous and... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.137-90 Dynamometer test run, gaseous... first period (505 seconds) is run. (2) Petroleum-fueled and methanol-fueled diesel vehicles. The...

  2. Gaseous emissions and toxic hazards associated with plastics in fire situations: A literature review

    NASA Technical Reports Server (NTRS)

    Junod, T. L.

    1976-01-01

    The hazards of plastics in fire situations, the gases emitted, the factors influencing the nature of these emissions, the characteristics of toxic gases, and the results of laboratory studies, are discussed. The literature pertaining to the pyrolysis and oxidation of plastics was reviewed. An effort was made to define the state of the art for determining the toxic gases emitted by plastics under fire conditions. Recommendations are made and research needs defined as a result of this review.

  3. DEPOSITION AND EMISSION OF GASEOUS MERCURY TO AND FROM LAKE MICHIGAN DURING THE LAKE MICHIGAN MASS BALANCE STUDY (JULY, 1994 - OCTOBER, 1995)

    EPA Science Inventory

    This paper presents measurements of dissolved gaseous mercury (DGM) concentrations in Lake Michigan and the application of a mechanistic approach to estimate deposition and emission fluxes of gaseous mercury (Hg2+ and Hg0) to and from Lake Michigan. Measurements of DGM concentr...

  4. [Emission characteristics of fine particles from grate firing boilers].

    PubMed

    Wang, Shu-Xiao; Zhao, Xiu-Juan; Li, Xing-Hua; Wei, Wei; Hao, Ji-Ming

    2009-04-15

    Grate firing boilers are the main type of Chinese industrial boilers, which accounts for 85% of the industrial boilers and is one of the most important emission sources of primary air pollutants in China. In this study, five boilers in three cities were selected and tested to measure the emission characteristics of PM2.5, and gaseous pollutants were applied by a compact dilution sampling system, which was developed for this field study. Results showed that particles mass size distributions for the five industrial boilers presented single peak or double peak, former peaks near 0.14 microm and the later peaks after 1.0 microm; the cyclone dust remover and wet scrubber dust remover had effective removal efficiencies not only to PM2.5, but also to PM1.0; and under the condition of same control techniques, grate firing boiler with high capacity has less PM2.5 emission than the boiler with low capacity. In the PM2.5 collected from flue gases, SO4(2-) was the most abundant ion, accounted for 20%-40% of the PM2.5; and C was the most abundant element (7.5%-31.8%), followed by S (8.4%-18.7%). Carbon balance method was applied to calculate the emission factors of these pollutants. The emission factors of PM2.5, NO, and SO2 were in the range of 0.046-0.486 g x kg(-1), 1.63-2.47 g x kg(-1), 1.35-9.95 g x kg(-1) respectively. The results are useful for the emission inventory development of industrial boilers and the source analysis of PM2.5 in atmospheric environment. PMID:19544990

  5. Reacting shock waves characteristics for biogas compared to other gaseous fuel

    NASA Astrophysics Data System (ADS)

    Wahid, Mazlan Abdul; Ujir, Haffis

    2012-06-01

    Present article aims to report an experimental study conducted to characterize the reacting shock waves for biogas compared to several other gaseous fuels. A dedicated experimental system which consists of a stainless steel tube with inner diameter of 100mm, a data acquisition system, ignition control unit and gas filling system was built in order to measure the characteristics of high speed reacting shock waves for synthetic biogas such as, pressure history, velocity and cell width. Two types of hydrocarbon fuels were used for comparison in this investigation; propane and natural gas with 92.7% methane. Biogas was synthetically produced by mixing 65% natural gas with 35% carbon dioxide. The oxygen concentration in the oxidizer mixture was diluted with nitrogen gas at various percentage of dilution. Results show that natural gas and biogas were not sensitive to detonation propagation compared to propane. For biogas, methane, and propane it was found that in smooth inner-wall tube, detonation will likely to occur if the percent of dilution gas is not more than approximately 8%, 10% and 35%, respectively. In order to decrease the tube length required for deflagration to detonation transition, an array of obstacles with identical blockage ratio was placed inside the tube near the ignition source. The effect of combustion wave-obstacle interaction was also investigated.

  6. Effects of gaseous sulphuric acid on diesel exhaust nanoparticle formation and characteristics.

    PubMed

    Rönkkö, Topi; Lähde, Tero; Heikkilä, Juha; Pirjola, Liisa; Bauschke, Ulrike; Arnold, Frank; Schlager, Hans; Rothe, Dieter; Yli-Ojanperä, Jaakko; Keskinen, Jorma

    2013-10-15

    Diesel exhaust gaseous sulphuric acid (GSA) concentrations and particle size distributions, concentrations, and volatility were studied at four driving conditions with a heavy duty diesel engine equipped with oxidative exhaust after-treatment. Low sulfur fuel and lubricant oil were used in the study. The concentration of the exhaust GSA was observed to vary depending on the engine driving history and load. The GSA affected the volatile particle fraction at high engine loads; higher GSA mole fraction was followed by an increase in volatile nucleation particle concentration and size as well as increase of size of particles possessing nonvolatile core. The GSA did not affect the number of nonvolatile particles. At low and medium loads, the exhaust GSA concentration was low and any GSA driven changes in particle population were not observed. Results show that during the exhaust cooling and dilution processes, besides critical in volatile nucleation particle formation, GSA can change the characteristics of all nucleation mode particles. Results show the dual nature of the nucleation mode particles so that the nucleation mode can include simultaneously volatile and nonvolatile particles, and fulfill the previous results for the nucleation mode formation, especially related to the role of GSA in formation processes. PMID:24044459

  7. Characteristics of Gaseous Diffusion Flames with High Temperature Combustion Air in Microgravity

    NASA Technical Reports Server (NTRS)

    Ghaderi, M.; Gupta, A. K.

    2003-01-01

    The characteristics of gaseous diffusion flames have been obtained using high temperature combustion air under microgravity conditions. The time resolved flame images under free fall microgravity conditions were obtained from the video images obtained. The tests results reported here were conducted using propane as the fuel and about 1000 C combustion air. The burner included a 0.686 mm diameter central fuel jet injected into the surrounding high temperature combustion air. The fuel jet exit Reynolds number was 63. Several measurements were taken at different air preheats and fuel jet exit Reynolds number. The resulting hybrid color flame was found to be blue at the base of the flame followed by a yellow color flame. The length and width of flame during the entire free fall conditions has been examined. Also the relative flame length and width for blue and yellow portion of the flame has been examined under microgravity conditions. The results show that the flame length decreases and width increases with high air preheats in microgravity condition. In microgravity conditions the flame length is larger with normal temperature combustion air than high temperature air.

  8. The benefits of China's efforts on gaseous pollutant control indicated by the bottom-up emissions and satellite observation

    NASA Astrophysics Data System (ADS)

    Xia, Y.; Zhao, Y.

    2015-12-01

    To evaluate the effectiveness of national policies of air pollution control, the emissions of SO2, NOX, CO and CO2 in China are estimated with a bottom-up method from 2000 to 2014, and vertical column densities (VCD) from satellite observation are used to evaluate the inter-annual trends and spatial distribution of emissions and the temporal and spatial patterns of ambient levels of gaseous pollutants across the country. In particular, an additional emission case named STD case, which combines the most recent issued emission standards for specific industrial sources, is developed for 2012-2014. The inter-annual trends in emissions and VCDs match well except for SO2, and the revised emissions in STD case improve the comparison, implying the benefits of emission control for most recent years. Satellite retrieval error, underestimation of emission reduction and improved atmospheric oxidization caused the differences between emissions and VCDs trend of SO2. Coal-fired power plants play key roles in SO2 and NOX emission reduction. As suggested by VCD and emission inventory, the control of CO in 11th five year plan (FYP) period was more effective than that in the 12th FYP period, while the SO2 appeared opposite. As the new control target added in 12th FYP, NOX emissions have been clearly decreased 4.3 Mt from 2011 to 2014, in contrast to the fast growth before 2011. The inter-annual trends in NO2 VCDs has the poorest correlation with vehicle ownership (R=0.796), due to the staged emission standard of vehicles. In developed regions, transportation has become the main pollutants emission source and we prove this by comparing VCDs of NO2 to VCDs of SO2. Moreover, air quality in mega cities has been evaluated based on satellite observation and emissions, and results indicate that Beijing suffered heavily from the emissions from Hebei and Tianjin, while the local emissions tend to dominate in Shanghai.

  9. Removal of 2-butoxyethanol gaseous emissions by biotrickling filtration packed with polyurethane foam.

    PubMed

    Pérez, M C; Álvarez-Hornos, F J; Engesser, K H; Dobslaw, D; Gabaldón, C

    2016-03-25

    The removal of 2-butoxyethanol from gaseous emissions was studied using two biotrickling filters (BTF1 and BTF2) packed with polyurethane foam. Two different inoculum sources were used: a pure culture of Pseudomonas sp. BOE200 (BTF1) and activated sludge from a municipal wastewater treatment plant (BTF2). The bioreactors were operated at inlet loads (ILs) of 130 and 195 g m(-3) hour(-1) and at an empty bed residence time (EBRT) of 12.5s. Under an IL of ∼130 g m(-3) hour(-1), BTF1 presented higher elimination capacities (ECs) than BTF2, with average values of 106±7 and 68±8 g m(-3) hour(-1), respectively. However, differences in ECs between BTFs were decreased by reducing the irrigation intervals from 1 min every 12 min to 1 min every 2 hours in BTF2. Average values of EC were 111±25 and 90±7 g m(-3) hour(-1) for BTF1 and BTF2, respectively, when working at an IL of ∼195 g m(-3) hour(-1). Microbial analysis revealed a significant shift in the microbial community of BTF1 inoculated with Pseudomonas sp. BOE200. At the end of the experiment, the species Microbacterium sp., Chryseobacterium sp., Acinetobacter sp., Pseudomonas sp. and Mycobacterium sp. were detected. In BTF2 inoculated with activated sludge, the denaturing gradient gel electrophoresis (DGGE) technique showed a diverse microbial community including species that was able to use 2-butoxyethanol as its carbon source, such as Pseudomonas aeruginosa and Pseudomonas putida as representative species. Although BTF1 inoculated with Pseudomonas sp. BOE200 and higher gas velocity (probably greater gas/liquid mass transfer rate) showed a slight improvement in performance, the use of activated sludge as inoculum seems to be a more feasible option for the industrial application of this technology. PMID:26596886

  10. Online characterization of regulated and unregulated gaseous and particulate exhaust emissions from two-stroke mopeds: a chemometric approach.

    PubMed

    Clairotte, M; Adam, T W; Chirico, R; Giechaskiel, B; Manfredi, U; Elsasser, M; Sklorz, M; DeCarlo, P F; Heringa, M F; Zimmermann, R; Martini, G; Krasenbrink, A; Vicet, A; Tournié, E; Prévôt, A S H; Astorga, C

    2012-03-01

    Two-stroke mopeds are a popular and convenient mean of transport in particular in the highly populated cities. These vehicles can emit potentially toxic gaseous and aerosol pollutants due to their engine technology. The legislative measurements of moped emissions are based on offline methods; however, the online characterization of gas and particulate phases offers great possibilities to understand aerosol formation mechanism and to adapt future emission standards. The purpose of this work was to study the emission behavior of two mopeds complying with different European emission standards (EURO-1 and EURO-2). A sophisticated set of online analyzers was applied to simultaneously monitor the gas phase and particulate phase of exhaust on a real time basis. The gaseous emission was analyzed with a high resolution Fourier transform infrared spectrometer (FTIR; nitrogen species) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-ToF-MS; polycyclic aromatic hydrocarbons: PAH), whereas the particulate phase was chemically characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS; organic, nitrate and chloride aerosol) and a multiangle absorption photometer (MAAP; black carbon). The physical characterization of the aerosol was carried out with a condensation particle counter (CPC; particle number concentration) and a fast mobility particle sizer (FMPS; size distribution in real time). In order to extract underlying correlation between gas and solid emissions, principal component analysis was applied to the comprehensive online dataset. Multivariate analysis highlighted the considerable effect of the exhaust temperature on the particles and heavy PAH emissions. The results showed that the after-treatment used to comply with the latest EURO-2 emission standard may be responsible for the production of more potentially harmful particles compared to the EURO-1 moped emissions. PMID:22304813

  11. A direct method of measuring gaseous emissions from naturally ventilated dairy barns

    NASA Astrophysics Data System (ADS)

    Joo, H. S.; Ndegwa, P. M.; Heber, A. J.; Bogan, B. W.; Ni, J.-Q.; Cortus, E. L.; Ramirez-Dorronsoro, J. C.

    2014-04-01

    Air pollutant emission rates from mechanically ventilated (MV) dairy barns are determined from the product of the differences in concentrations of pollutants in air at the inlet and exhaust points and the corresponding ventilation rates. In contrast to well defined entry and exit points in MV barns, large area air inlets or outlets characterize naturally ventilated (NV) freestall dairy barns. Complicating this scenario even more, pertinent airflow characteristics (velocity and direction) necessary for determining ventilation rates vary continuously, both temporally and spatially. This paper describes implementation of a direct method, generally equivalent to the approach used for MV barns, for determining air emission rates of NV barns. Ultrasonic anemometers (sonics) located at salient points in the barn openings mapped air inflow and outflow velocities necessary to calculate ventilation rates. Pollutant concentrations in the air entering or leaving the barn during a given period were measured at sampling points located next to the anemometers. The air inflow rates were, in general, higher than the air outflow rates from the barns, but diurnal profiles were similar. The observed ventilation characteristics were consistent with prevailing wind directions. Air inflows were observed predominantly at windward openings of the barn, while the outflows were mainly at the barn's leeward openings. Results indicated that either: (i) the average of the air inflow and outflow rates (averaging approach), or (ii) the air inflow rates (inflow-only approach) were credible representations of ventilation rates. Results also revealed use of an on-site weather station and one sonic mounted in the middle of each wall of the barn as a possible approach for determining barn ventilation rates. The suggested use of ventilation rates for interpolating missing concentrations from intermittent gas measurements could potentially increase the integrity of emission rates at significantly lower

  12. Variational Characteristics and Implications of Gaseous Elemental Mercury for Three Continuous Typhoons in China.

    PubMed

    Gao, Zhiqiang; Sun, Jiaren; Liu, Ming; Chen, Laiguo; Lei, Yutao; Xie, Donghai; Liu, Jingyong; Li, Jie; Xu, Zhencheng

    2016-05-01

    Coupling air pollutants with particular meteorological conditions can induce air pollution episodes. To our knowledge, how typhoons influence mercury (Hg) as an extreme weather phenomena has not been reported. Gaseous elemental Hg (GEM) was measured during a time period (from September 16, 2011 to October 9, 2011) that included three typhoons (Haitang, Nesat, and Nalgae) at the Wuzhishan National Atmospheric Background Station. The GEM concentration during these typhoons ranged from 1.81 to 4.73 ng/m(3) (2.97 ± 0.58 ng/m(3)), 1.27 to 4.42 ng/m(3) (2.69 ± 0.83 ng/m(3)), and 1.43 to 2.99 ng/m(3) (2.47 ± 0.32 ng/m(3)), which was higher than for the non-typhoon period (1.14-2.93 ng/m(3), 1.61 ± 0.52 ng/m(3)). Simultaneously, the three typhoon periods exhibited a significant positive correlation between the GEM concentration and wind speed. These results differ from the common belief that lower pollutant concentrations will occur due to a typhoon accelerating pollutant diffusion. Changes in the wind direction and long range pollutant transport from the Chinese mainland can reasonably account for this abnormality. There was a significantly positive correlation between the GEM and SO2, NO x , CO, and O3 levels during the three typhoons periods, which indicates they came from the same sources or areas. A backward trajectory analysis and the concentration weighted field at our monitoring site indicated that clean air masses mainly came from Southeast Asia or the southeast and northeast sea surfaces during non-typhoon periods, while polluted air masses came from the Chinese mainland during the three typhoon periods. The results implied that the increased GEM concentrations in the Wuzhi Mountain were caused by the long-range atmospheric transport of Hg from the Chinese mainland during the typhoon periods. The combustion of coal may be the main emission sources. PMID:26376989

  13. Emissions characteristics of modern oil heating equipment

    SciTech Connect

    Krajewski, R.; Celebi, Y.; Coughlan, R.; Butcher, T.; McDonald, R.J.

    1990-07-01

    Over the last 10 years there have been some very interesting developments in oil heating. These include higher static pressure burners, air atomizing nozzles, low firing rate nozzles, low heat loss combustion chambers and condensing boilers and furnaces. The current data base on the emissions characteristics of oil-fired residential heating equipment is based primarily on data taken in the 1970's. The objective of the work described in this report is to evaluate the effects of recent developments in oil-fired equipment on emissions. Detailed emissions measurements have been made on a number of currently available residential oil burners and whole systems selected to represent recent development trends. Some additional data was taken with equipment which is in the prototype stage. These units are a prevaporizing burner and a retention head burner modified with an air atomizing nozzle. Measurements include No{sub x}, smoke numbers, CO, gas phase hydrocarbon emissions and particulate mass emission rates. Emissions of smoke, CO and hydrocarbons were found to be significantly greater under cyclic operation for all burners tested. Generally, particulate emission rates were found to be 3 to 4 times greater in cyclic operation than in steady state. Air atomized burners were found to be capable of operation at much lower excess air levels than pressure atomized burners without producing significant amounts of smoke. As burner performance is improved, either through air atomization or prevaporization of the fuel, there appears to be a general trend towards producing CO at lower smoke levels as excess air is decreased. The criteria of adjusting burners for trace smoke may need to be abandoned for advanced burners and replaced with an adjustment for specific excess air levels. 17 refs., 15 figs., 6 tabs.

  14. Parametric experimental studies on mixing characteristics within a low area ratio rectangular supersonic gaseous ejector

    NASA Astrophysics Data System (ADS)

    Karthick, S. K.; Rao, Srisha M. V.; Jagadeesh, G.; Reddy, K. P. J.

    2016-07-01

    We use the rectangular gaseous supersonic ejector as a platform to study the mixing characteristics of a confined supersonic jet. The entrainment ratio (ER) of the ejector, the non-mixed length (LNM), and potential core length (LPC) of the primary supersonic jet are measures to characterize mixing within the supersonic ejector. Experiments are carried out on a low area ratio rectangular supersonic ejector with air as the working fluid in both primary and secondary flows. The design Mach number of the nozzle (MPD = 1.5-3.0) and primary flow stagnation pressure (Pop = 4.89-9.89 bars) are the parameters that are varied during experimentation. Wall static pressure measurements are carried out to understand the performance of the ejector as well as to estimate the LNM (the spatial resolution is limited by the placement of pressure transducers). Well-resolved flow images (with a spatial resolution of 50 μm/pixel and temporal resolution of 1.25 ms) obtained through Planar Laser Mie Scattering (PLMS) show the flow dynamics within the ejector with clarity. The primary flow and secondary flow are seeded separately with acetone that makes the LNM and LPC clearly visible in the flow images. These parameters are extracted from the flow images using in-house image processing routines. A significant development in this work is the definition of new scaling parameters within the ejector. LNM, non-dimensionalized with respect to the fully expanded jet height hJ, is found to be a linear function of the Mach number ratio (Mach number ratio is defined as the ratio of design Mach number (MPD) and fully expanded Mach number (MPJ) of the primary jet). This definition also provides a clear demarcation of under-expanded and over-expanded regimes of operation according to [MPD/MPJ] > 1 and [MPD/MPJ] < 1, respectively. It is observed that the ER increased in over-expanded mode (to 120%) and decreased in under-expanded mode (to 68%). Similarly, LNM decreased (to 21.8%) in over-expanded mode

  15. Real-time gaseous, PM and ultrafine particle emissions from a modern marine engine operating on biodiesel.

    PubMed

    Jayaram, Varalakshmi; Agrawal, Harshit; Welch, William A; Miller, J Wayne; Cocker, David R

    2011-03-15

    Emissions from harbor-craft significantly affect air quality in populated regions near ports and inland waterways. This research measured regulated and unregulated emissions from an in-use EPA Tier 2 marine propulsion engine on a ferry operating in a bay following standard methods. A special effort was made to monitor continuously both the total Particulate Mass (PM) mass emissions and the real-time Particle Size Distribution (PSD). The engine was operated following the loads in ISO 8178-4 E3 cycle for comparison with the certification standards and across biodiesel blends. Real-time measurements were also made during a typical cruise in the bay. Results showed the in-use nitrogen oxide (NOx) and PM(2.5) emission factors were within the not to exceed standard for Tier 2 marine engines. Comparing across fuels we observed the following: a) no statistically significant change in NO(x) emissions with biodiesel blends (B20, B50); b) ∼ 16% and ∼ 25% reduction of PM(2.5) mass emissions with B20 and B50 respectively; c) a larger organic carbon (OC) to elemental carbon (EC) ratio and organic mass (OM) to OC ratio with B50 compared to B20 and B0; d) a significant number of ultrafine nuclei and a smaller mass mean diameter with increasing blend-levels of biodiesel. The real-time monitoring of gaseous and particulate emissions during a typical cruise in the San Francisco Bay (in-use cycle) revealed important effects of ocean/bay currents on emissions: NO(x) and CO(2) increased 3-fold; PM(2.5) mass increased 6-fold; and ultrafine particles disappeared due to the effect of bay currents. This finding has implications on the use of certification values instead of actual in-use emission values when developing inventories. Emission factors for some volatile organic compounds (VOCs), carbonyls, and poly aromatic hydrocarbons (PAHs) are reported as supplemental data. PMID:21344849

  16. 40 CFR 86.1310-2007 - Exhaust gas sampling and analytical system for gaseous emissions from heavy-duty diesel-fueled...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Exhaust gas sampling and analytical system for gaseous emissions from heavy-duty diesel-fueled engines and particulate emissions from all engines. 86.1310-2007 Section 86.1310-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL...

  17. Pollutant Emissions and Lean Blowoff Limits of Fuel Flexible Burners Operating on Gaseous Renewable and Fossil Fuels

    NASA Astrophysics Data System (ADS)

    Colorado, Andres

    This study provides an experimental and numerical examination of pollutant emissions and stability of gaseous fueled reactions stabilized with two premixed-fuel-flexible and ultra-low NOx burner technologies. Both burners feature lean combustion technology to control the formation of nitrogen oxides (NOx). The first fuel--flexible burner is the low-swirl burner (LSB), which features aerodynamic stabilization of the reactions with a divergent flow-field; the second burner is the surface stabilized combustion burner (SSCB), which features the stabilization of the reactions on surface patterns. For combustion applications the most commonly studied species are: NOx, carbon monoxide (CO), and unburned hydrocarbons (UHC). However these are not the only pollutants emitted when burning fossil fuels; other species such as nitrous oxide (N2O), ammonia (NH3) and formaldehyde (CH2O) can be directly emitted from the oxidation reactions. Yet the conditions that favor the emission of these pollutants are not completely understood and require further insight. The results of this dissertation close the gap existing regarding the relations between emission of pollutants species and stability when burning variable gaseous fuels. The results of this study are applicable to current issues such as: 1. Current combustion systems operating at low temperatures to control formation of NOx. 2. Increased use of alternative fuels such as hydrogen, synthetic gas and biogas. 3. Increasing recognition of the need/desire to operate combustion systems in a transient manner to follow load and to offset the intermittency of renewable power. 4. The recent advances in measurement methods allow us to quantify other pollutants, such as N 2O, NH3 and CH2O. Hence in this study, these pollutant species are assessed when burning natural gas (NG) and its binary mixtures with other gaseous fuels such as hydrogen (H2), carbon dioxide (CO2), ethane (C 2H6) and propane (C3H8) at variable operation modes including

  18. Application of multicriteria decision making methods to compression ignition engine efficiency and gaseous, particulate, and greenhouse gas emissions.

    PubMed

    Surawski, Nicholas C; Miljevic, Branka; Bodisco, Timothy A; Brown, Richard J; Ristovski, Zoran D; Ayoko, Godwin A

    2013-02-19

    Compression ignition (CI) engine design is subject to many constraints, which present a multicriteria optimization problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient but must also deliver low gaseous, particulate, and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming is minimized. Consequently, this study undertakes a multicriteria analysis, which seeks to identify alternative fuels, injection technologies, and combustion strategies that could potentially satisfy these CI engine design constraints. Three data sets are analyzed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of (1) an ethanol fumigation system, (2) alternative fuels (20% biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and (3) various biodiesel fuels made from 3 feedstocks (i.e., soy, tallow, and canola) tested at several blend percentages (20-100%) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20% by energy) at moderate load, high percentage soy blends (60-100%), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem. Further research is, however, required to reduce reactive oxygen species (ROS) emissions with alternative fuels and to deliver technologies that do not significantly reduce the median diameter of particle emissions. PMID:23343018

  19. DairyGEM: software for evaluating gaseous emissions from dairy farms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The evaluation of mitigation strategies for dairy farms is complex because strategies that reduce one type or source of emission may increase others. A proper evaluation requires a comprehensive assessment of all important emissions and their interactions. Measurement of emissions from dairy farms i...

  20. Particulate matter, gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) in an urban traffic tunnel of China: Emission from on-road vehicles and gas-particle partitioning.

    PubMed

    Liu, Ying; Gao, Yi; Yu, Na; Zhang, Chenkai; Wang, Siyao; Ma, Limin; Zhao, Jianfu; Lohmann, Rainer

    2015-09-01

    Traffic vehicles are a main source of polycyclic aromatic hydrocarbon (PAH) emission in urban area. It is vital to understand PAH gas-particle partitioning in real traffic environment and assess PAH vehicular emission factors in developing China. Concentrations of particulate matter, carbonaceous products, gaseous and particulate PAHs were measured during 2011-2012 in a road tunnel of Shanghai, China. Time variation of them reflected basic traffic operation of the tunnel. PAHs approached equilibrium between gas and particle phases and the partitioning was predicted better by a dual sorption model combining absorption into organic matter and adsorption onto black carbon. The influence of black carbon adsorption on the partitioning behavior of PAHs was important. The difference in isomer ratios of gaseous and particulate PAHs was attributed to PAH contributions from different traffic-related PAHs sources. Real-world vehicle emission factors of gaseous and particulate PAHs were quantified based on fuel burned model and vehicle kilometer traveled model. PMID:25911047

  1. Effect of thermionic cathode heating current self-magnetic field on gaseous plasma generator characteristics

    NASA Astrophysics Data System (ADS)

    Lopatin, I. V.; Akhmadeev, Yu. H.; Koval, N. N.

    2015-10-01

    The performance capabilities of the PINK, a plasma generator with a thermionic cathode mounted in the cavity of a hollow cathode, depending for its operation on a non-self-sustained low-pressure gas discharge have been investigated. It has been shown that when a single-filament tungsten cathode 2 mm in diameter is used and the peak filament current is equal to or higher than 100 A, the self-magnetic field of the filament current significantly affects the discharge current and voltage waveforms. This effect is due to changes in the time and space distributions of the emission current density from the hot cathode. When the electron mean free path is close to the characteristic dimensions of the thermionic cathode, the synthesized plasma density distribution is nonuniform and the cathode is etched nonuniformly. The cathode lifetime in this case is 8-12 h. Using a cathode consisting of several parallel-connected tungsten filaments ˜0.8 mm in diameter moderates the effect of the self-magnetic field of the filament current and nearly doubles the cathode lifetime. The use of this type of cathode together with a discharge igniting electrode reduces the minimum operating pressure in the plasma generator to about one third of that required for the generator operation with a single-filament cathode (to 0.04 Pa).

  2. Effect of thermionic cathode heating current self-magnetic field on gaseous plasma generator characteristics.

    PubMed

    Lopatin, I V; Akhmadeev, Yu H; Koval, N N

    2015-10-01

    The performance capabilities of the PINK, a plasma generator with a thermionic cathode mounted in the cavity of a hollow cathode, depending for its operation on a non-self-sustained low-pressure gas discharge have been investigated. It has been shown that when a single-filament tungsten cathode 2 mm in diameter is used and the peak filament current is equal to or higher than 100 A, the self-magnetic field of the filament current significantly affects the discharge current and voltage waveforms. This effect is due to changes in the time and space distributions of the emission current density from the hot cathode. When the electron mean free path is close to the characteristic dimensions of the thermionic cathode, the synthesized plasma density distribution is nonuniform and the cathode is etched nonuniformly. The cathode lifetime in this case is 8-12 h. Using a cathode consisting of several parallel-connected tungsten filaments ∼0.8 mm in diameter moderates the effect of the self-magnetic field of the filament current and nearly doubles the cathode lifetime. The use of this type of cathode together with a discharge igniting electrode reduces the minimum operating pressure in the plasma generator to about one third of that required for the generator operation with a single-filament cathode (to 0.04 Pa). PMID:26520947

  3. Effect of thermionic cathode heating current self-magnetic field on gaseous plasma generator characteristics

    SciTech Connect

    Lopatin, I. V. Akhmadeev, Yu. H.; Koval, N. N.

    2015-10-15

    The performance capabilities of the PINK, a plasma generator with a thermionic cathode mounted in the cavity of a hollow cathode, depending for its operation on a non-self-sustained low-pressure gas discharge have been investigated. It has been shown that when a single-filament tungsten cathode 2 mm in diameter is used and the peak filament current is equal to or higher than 100 A, the self-magnetic field of the filament current significantly affects the discharge current and voltage waveforms. This effect is due to changes in the time and space distributions of the emission current density from the hot cathode. When the electron mean free path is close to the characteristic dimensions of the thermionic cathode, the synthesized plasma density distribution is nonuniform and the cathode is etched nonuniformly. The cathode lifetime in this case is 8–12 h. Using a cathode consisting of several parallel-connected tungsten filaments ∼0.8 mm in diameter moderates the effect of the self-magnetic field of the filament current and nearly doubles the cathode lifetime. The use of this type of cathode together with a discharge igniting electrode reduces the minimum operating pressure in the plasma generator to about one third of that required for the generator operation with a single-filament cathode (to 0.04 Pa)

  4. Investigation on the gaseous and particulate emissions of a compression ignition engine fueled with diesel-dimethyl carbonate blends.

    PubMed

    Cheung, C S; Zhu, Ruijun; Huang, Zuohua

    2011-01-01

    The effect of dimethyl carbonate (DMC) on the gaseous and particulate emissions of a diesel engine was investigated using Euro V diesel fuel blended with different proportions of DMC. Combustion analysis shows that, with the blended fuel, the ignition delay and the heat release rate in the premixed combustion phase increase, while the total combustion duration and the fuel consumed in the diffusion combustion phase decrease. Compared with diesel fuel, with an increase of DMC in the blended fuel, the brake thermal efficiency is slightly improved but the brake specific fuel consumption increases. On the emission side, CO increases significantly at low engine load but decreases at high engine load while HC decreases slightly. NO(x) reduces slightly but the reduction is not statistically significant, while NO(2) increases slightly. Particulate mass and number concentrations decrease upon using the blended fuel while the geometric mean diameter of the particles shifts towards smaller size. Overall speaking, diesel-DMC blends lead to significant improvement in particulate emissions while the impact on CO, HC and NO(x) emissions is small. PMID:21081245

  5. Ethanol, isobutanol, and biohydrocarbons as gasoline components in relation to gaseous emissions and particulate matter.

    PubMed

    Aakko-Saksa, Päivi T; Rantanen-Kolehmainen, Leena; Skyttä, Eija

    2014-09-01

    The exhaust emissions of three cars using different biofuels were explored at a temperature of -7 °C. The biofuels studied contained both low- and high-concentration ethanol blends, isobutanol, and biohydrocarbons. A multipoint fuel injection car (MPFI), direct-injection spark-ignition car (DISI), and flex-fuel car (FFV) represented three different spark-ignition-car technologies. At -7 °C, substantial emissions were observed for the three cars, and differences were found among ethanol, isobutanol, and biohydrocarbons as fuel components. For example, E85 resulted in high acetaldehyde, formaldehyde, ethanol, ethene, and acetylene emissions when compared to E30 or lower ethanol concentrations. Isobutanol-containing fuel showed elevated butyraldehyde, methacrolein, and isobutanol emissions. The highest particulate matter (PM) emissions, associated polyaromatic hydrocarbon (PAH) and indirect mutagenicity emissions were detected with the DISI car. Oxygenated fuels reduced PM emissions and associated priority PAH emissions in the DISI car. PM and PAH emissions from the MPFI and FFV cars were generally low. A combination of 10% ethanol and biohydrocarbon components did not change emissions significantly when compared to ethanol-only-containing E10 gasoline. Therefore, a combination of ethanol or isobutanol with biohydrocarbon components offers an option to reach high gasoline bioenergy content for E10-compatible cars. PMID:25075876

  6. Historical gaseous and primary aerosol emissions in the United States from 1990 to 2010

    NASA Astrophysics Data System (ADS)

    Xing, J.; Pleim, J.; Mathur, R.; Pouliot, G.; Hogrefe, C.; Gan, C.-M.; Wei, C.

    2013-08-01

    An accurate description of emissions is crucial for model simulations to reproduce and interpret observed phenomena over extended time periods. In this study, we used an approach based on activity data to develop a consistent series of spatially resolved emissions in the United States from 1990 to 2010. The state-level anthropogenic emissions of SO2, NOx, CO, NMVOC (non-methane volatile organic compounds), NH3, PM10 and PM2.5 for a total of 49 sectors were estimated based on several long-term databases containing information about activities and emission controls. Activity data for energy-related stationary sources were derived from the State Energy Data System. Corresponding emission factors reflecting implemented emission controls were calculated back from the National Emissions Inventory (NEI) for seven years (i.e., 1990, 1995, 1996, 1999, 2001, 2002 and 2005), and constrained by the AP-42 (US EPA's Compilation of Air Pollutant Emissions Factors) dataset. Activity data for mobile sources including different types of highway vehicles and non-highway equipment were obtained from highway statistics reported by the Federal Highway Administration. The trends in emission factors for highway mobile source were informed by the 2011 National Transportation Statistics. Emissions for all non-energy-related sources were either scaled by the growth ratio of activity indicators or adjusted based on the NEI trends report. Because of the strengthened control efforts, particularly for the power sector and mobile sources, emissions of all pollutants except NH3 were reduced by half over the last two decades. The emission trends developed in this study are comparable with the NEI trend report and EDGAR (Emissions Database for Global Atmospheric Research) data, but better constrained by trends in activity data. Reductions in SO2, NOx, CO and EC (speciation of PM2.5 by SMOKE, Sparse Matrix Operator Kernel Emissions) emissions agree well with the observed changes in ambient SO2, NO2

  7. Historical gaseous and primary aerosol emissions in the United States from 1990-2010

    NASA Astrophysics Data System (ADS)

    Xing, J.; Pleim, J.; Mathur, R.; Pouliot, G.; Hogrefe, C.; Gan, C.-M.; Wei, C.

    2012-11-01

    An accurate description of emissions is crucial for model simulations to reproduce and interpret observed phenomena over extended time periods. In this study, we used an approach based on activity data to develop a consistent series of spatially resolved emissions in the United States from 1990 to 2010. The state-level anthropogenic emissions of SO2, NOx, CO, NMVOC, NH3, PM10 and PM2.5 for a total of 49 sectors were estimated based on several long-term databases containing information about activities and emission controls. Activity data for energy-related stationary sources were derived from the State Energy Data System. Corresponding emission factors reflecting implemented emission controls were calculated back from the National Emission Inventory (NEI) for seven years (i.e. 1990, 1995, 1996, 1999, 2001, 2002 and 2005), and constrained by the AP-42 (US EPA's Compilation of Air Pollutant Emissions Factors) dataset. Activity data for mobile sources including different types of highway vehicles and non-highway equipments were obtained from highway statistics reported by the Federal Highway Administration. The trends in emission factors for highway mobile source were informed by the 2011 National Transportation Statistics. Emissions for all non-energy related sources were either scaled by the growth ratio of activity indicators or adjusted based on the NEI trends report. Because of the strengthened control efforts, particularly for the power sector and mobile sources, emissions of all pollutants except NH3 were reduced by half over the last two decades. The emission trends developed in this study are comparable with the NEI trend report and EDGAR (Emissions Database for Global Atmospheric Research) data, but better constrained by trends in activity data. Reductions in SO2 and NOx emissions agree well with the observed changes in ambient SO2 and NO2 concentrations, suggesting that the various controls on SO2 and NOx emissions implemented over the last two decades are

  8. A BOUNDARY LAYER SAMPLING METHODOLOGY FOR MEASURING GASEOUS EMISSIONS FROM CAFO'S

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various methodologies have been employed to measure CAFO emissions (e.g. flux chambers, lasers, and stationary towers), but these methods are usually limited in their ability to fully characterize the emission plume from a heterogeneous farm, and thus are limited in their ability to quantify total e...

  9. 40 CFR 62.15175 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., maintain, and operate continuous emission monitoring systems for oxygen (or carbon dioxide), sulfur dioxide... emission monitoring system for sulfur dioxide, nitrogen oxides, and oxygen (or carbon dioxide) at the... part 60. (c) You must monitor the oxygen (or carbon dioxide) concentration at each location where...

  10. 40 CFR 60.1720 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., maintain, and operate continuous emission monitoring systems for oxygen (or carbon dioxide), sulfur dioxide... emission monitoring systems for sulfur dioxide, nitrogen oxides, and oxygen (or carbon dioxide) at the... oxygen (or carbon dioxide) concentration at each location where you monitor sulfur dioxide and...

  11. 40 CFR 62.15175 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., maintain, and operate continuous emission monitoring systems for oxygen (or carbon dioxide), sulfur dioxide... emission monitoring system for sulfur dioxide, nitrogen oxides, and oxygen (or carbon dioxide) at the... part 60. (c) You must monitor the oxygen (or carbon dioxide) concentration at each location where...

  12. 40 CFR 60.1720 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., maintain, and operate continuous emission monitoring systems for oxygen (or carbon dioxide), sulfur dioxide... emission monitoring systems for sulfur dioxide, nitrogen oxides, and oxygen (or carbon dioxide) at the... oxygen (or carbon dioxide) concentration at each location where you monitor sulfur dioxide and...

  13. 40 CFR 60.1720 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., maintain, and operate continuous emission monitoring systems for oxygen (or carbon dioxide), sulfur dioxide... emission monitoring systems for sulfur dioxide, nitrogen oxides, and oxygen (or carbon dioxide) at the... oxygen (or carbon dioxide) concentration at each location where you monitor sulfur dioxide and...

  14. 40 CFR 62.15175 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., maintain, and operate continuous emission monitoring systems for oxygen (or carbon dioxide), sulfur dioxide... emission monitoring system for sulfur dioxide, nitrogen oxides, and oxygen (or carbon dioxide) at the... part 60. (c) You must monitor the oxygen (or carbon dioxide) concentration at each location where...

  15. Historical gaseous and primary aerosol emissions in the United States from 1990-2010

    EPA Science Inventory

    An accurate description of emissions is crucial for model simulations to reproduce and interpret observed phenomena over extended time periods. In this study, we used an approach based on activity data to develop a consistent series of spatially resolved emissions in the United S...

  16. Theoretical emission line ratios for [Fe III] and [Fe VII] applicable to the optical and infrared spectra of gaseous nebulae.

    PubMed

    Keenan, F P; Aller, L H; Ryans, R S; Hyung, S

    2001-08-14

    Recent calculations of electron impact excitation rates and Einstein A-coefficients for transitions among the 3d(6) levels of Fe III and among the 3d(2) levels of Fe VII are used to derive theoretical emission line ratios applicable to the optical and infrared spectra of gaseous nebulae. Results for [Fe III] are generated for electron temperatures T(e) = 7,000-20,000 K and densities N(e) = 10(2)-10(8) cm(-3), whereas those for [Fe VII] are provided for T(e) = 10,000-30,000 K and N(e) = 10(2)-10(8) cm(-3). The theoretical line ratios are significantly different in some instances from earlier calculations and resolve discrepancies between theory and observation found for the planetary nebulae IC 4997 and NGC 7027. PMID:11493676

  17. Theoretical emission line ratios for [Fe III] and [Fe VII] applicable to the optical and infrared spectra of gaseous nebulae

    PubMed Central

    Keenan, Francis P.; Aller, Lawrence H.; Ryans, Robert S. I.; Hyung, Siek

    2001-01-01

    Recent calculations of electron impact excitation rates and Einstein A-coefficients for transitions among the 3d6 levels of Fe III and among the 3d2 levels of Fe VII are used to derive theoretical emission line ratios applicable to the optical and infrared spectra of gaseous nebulae. Results for [Fe III] are generated for electron temperatures Te = 7,000–20,000 K and densities Ne = 102-108 cm−3, whereas those for [Fe VII] are provided for Te = 10,000–30,000 K and Ne = 102-108 cm−3. The theoretical line ratios are significantly different in some instances from earlier calculations and resolve discrepancies between theory and observation found for the planetary nebulae IC 4997 and NGC 7027. PMID:11493676

  18. Gaseous mercury emissions from unsterilized and sterilized soils: the effect of temperature and UV radiation.

    PubMed

    Choi, Hyun-Deok; Holsen, Thomas M

    2009-05-01

    Mercury (Hg) emissions from the soils taken from two different sites (deciduous and coniferous forests) in the Adirondacks were measured in outdoor and laboratory experiments. Some of the soil samples were irradiated to eliminate biological activity. The result from the outdoor measurements with different soils suggests the Hg emission from the soils is partly limited by fallen leaves covering the soils which helps maintain relatively high soil moisture and limits the amount of heat and solar radiation reaching the soil surface. In laboratory experiments exposure to UV-A (365 nm) had no significant effect on the Hg emissions while the Hg emissions increased dramatically during exposure to UV-B (302 nm) light suggesting UV-B directly reduced soil-associated Hg. Overall these results indicate that for these soils biotic processes have a relatively constant and smaller influence on the Hg emission from the soil than the more variable abiotic processes. PMID:19155110

  19. 47 CFR 2.201 - Emission, modulation, and transmission characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Emission, modulation, and transmission characteristics. 2.201 Section 2.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Emissions § 2.201 Emission, modulation, and transmission characteristics....

  20. 47 CFR 2.201 - Emission, modulation, and transmission characteristics.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Emission, modulation, and transmission characteristics. 2.201 Section 2.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Emissions § 2.201 Emission, modulation, and transmission characteristics....

  1. 47 CFR 2.201 - Emission, modulation, and transmission characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Emission, modulation, and transmission characteristics. 2.201 Section 2.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Emissions § 2.201 Emission, modulation, and transmission characteristics....

  2. 47 CFR 2.201 - Emission, modulation, and transmission characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Emission, modulation, and transmission characteristics. 2.201 Section 2.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Emissions § 2.201 Emission, modulation, and transmission characteristics....

  3. Characterization of gaseous pollutant and particulate matter emission rates from a commercial broiler operation part II: Correlated emission rates

    NASA Astrophysics Data System (ADS)

    Roumeliotis, Taylor S.; Dixon, Brad J.; Van Heyst, Bill J.

    2010-10-01

    Emission rates of ammonia, acid gases, inorganic aerosols, methane, and size fractionated particulate matter were measured from a commercial broiler facility. This paper discusses the statistically influential parameters on numerous pollutants' emission from a broiler chicken facility and generates emission correlations to fill data gaps and develop averaged emission factors. Live mass of the birds was commonly a significant variable to each pollutant's emission. Some variables significantly impacted the pollutants' emissions, such as litter moisture content, but were measured discretely and cannot be used for filling in data gaps. House parameter correlations were, therefore, developed using parameters measured at the facility, such as indoor temperature, relative humidity, and the live mass of the birds, and relied on the mutual behaviour of discretely measured explanatory parameters and continuously monitored confounding variables. The live mass and the difference in the indoor temperature and the house set-point temperature were the most significant variables in each pollutant's correlation. The correlations predicted each pollutants emission to within 20% (total mass basis) over most broiler production cycles. Their validation on independent datasets also successfully estimated the flocks' emissions to within 3%. Emission factors (EFs) were developed for methane, ammonia, and size fractionated particulate matter using measured data and correlated emissions to fill in data gaps. PM 10 (particulate matter ≤10 microns) EFs were estimated to be 4.6 and 5.9 g d -1 [Animal Unit, AU] -1 for five and six week production cycles, respectively. PM 2.5 (PM ≤ 2.5 microns) EFs were 0.8 and 1.4 g d -1 AU -1 for five and six week cycles, respectively. Ammonia and methane emission factors were estimated at 120.8 and 197.0 g d -1 AU -1, respectively for a five week production cycle.

  4. Heterogeneity of gaseous emissions in soils-spatial vs temporal variability

    NASA Astrophysics Data System (ADS)

    Cardenas, Laura; Chadwick, David; Misselbrook, Tom; Donovan, Neil; Dunn, Rob; Griffith, Bruce; Orr, Robert; Smith, Keith; Rees, Robert M.; Bell, Madeleine; Watson, Catherine; McGeough, Karen; McNeill, Gavin; Williams, John; Cloy, Joanna; Thorman, Rachel; Dhanoa, Dan

    2015-04-01

    Nitrous oxide (N2O) plays a dual role in the atmosphere as a greenhouse gas and via its influence on stratospheric ozone chemistry. The main source of N2O is agricultural soil, with an estimated 96 kt emitted from this source in the UK in 2012 (ca. 83% of the total UK N2O emissions). Microbial transformations such as nitrification, denitrification and chemodenitrification are responsible for these emissions. Soil texture and structure and land management practices (including presence of livestock) -- soil wetness, aeration, temperature and mineral N content -- influence the magnitude of the emissions. Heterogeneity in nutrient distribution and moisture, i.e. hot spots, create spatial variations in the main drivers of these transformations. Studies at laboratory scale are aimed to minimize the variability encountered in the field but although they provide important information on the controlling factors of the soil processes, they are not useful for real quantification. Daily and seasonal variation (temporal) in soil conditions (chemistry, physics and biology) and thus in emissions also occurs. This variability makes it a difficult challenge to quantify emissions and currently makes the soil source the largest contributor to the overall uncertainty of the UK greenhouse gas inventory. Here we present results of a statistical study on the variability of N2O emissions from measurements using the static chamber technique for a variety of N sources. Results from measurements using automated chambers are also presented. Part of the work was funded by the UK government to improve the quantification of this source by measuring emissions from sites with contrasting soil, climate and land management combinations. We also include results from measurements carried out with automated chambers on the UK National Capability Farm Platform in the South West of England. The results show that spatial variability largely contributes to the uncertainty of emissions but temporal

  5. Gaseous and particulate composition of fresh and aged emissions of diesel, RME and CNG buses using Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Psichoudaki, Magda; Le Breton, Michael; Hallquist, Mattias; Watne, Ågot; Hallquist, Asa

    2016-04-01

    Urban air pollution is becoming a significant global problem, especially for large cities around the world. Traffic emissions contribute significantly to both elevated particle concentrations and to gaseous pollutants in cities. The latter also have the potential of forming more particulate mass via their photochemical oxidation in the atmosphere. The International Agency for Research on Cancer and the US EPA have characterised diesel exhausts as a likely human carcinogen that can also contribute to other health problems. In order to meet the challenges with increased transportation and enhanced greenhouse gas emissions, the European Union have decided on a 10% substitution of traditional fuels in the road transport sector by alternative fuels (e.g. biodiesel, CNG) before the year 2020. However, it is also important to study the influence of fuel switches on other primary pollutants as well as the potential to form secondary aerosol mass. This work focuses on the characterisation of the chemical composition of the gas and the condensed phase of fresh bus emissions during acceleration, in order to mimic the exhaust plume that humans would inhale under realistic conditions. In addition, photochemical aging of the exhaust emissions was achieved by employing a Potential Aerosol Mass (PAM) flow reactor, allowing the characterization of the composition of the corresponding aged emissions. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the chamber. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in these measurements corresponded to a range from 4 to 8 days in the atmosphere. During June and July 2015, a total of 29 buses, 5 diesel, 13 CNG and 11 RME (rapeseed methyl ester), were tested in two different locations with limited influence from other types of emissions and traffic

  6. EFFECT OF VEHICLE CHARACTERISTICS ON UNPAVED ROAD DUST EMISSIONS

    EPA Science Inventory

    This paper presents PM10 fugitive dust emission factors for a range of vehicles types and examines the influence of vehicle and wake characteristics on the strength of emissions from an unpaved road.

  7. DIVALENT INORGANIC REACTIVE GASEOUS MERCURY EMISSIONS FROM A MERCURY CELL CHLOR-ALKALI PLANT AND ITS IMPACT ON NEAR FIELD ATMOSPHERIC DRY DEPOSITION

    EPA Science Inventory

    The emission of inorganic divalent reactive gaseous mercury (RGM) from a mercury cell chlor-alkali plant (MCCAP) cell building and the impact on near field (100 km) dry deposition was investigated as part of a larger collaborative study between EPA, University of Michigan, Oak ...

  8. The Investigation of Reducing PAHs Emission from Coal Pyrolysis by Gaseous Catalytic Cracking

    PubMed Central

    Wang, Yulong; Zhao, Ruifang; Zhang, Chun; Li, Guanlong; Zhang, Jing; Li, Fan

    2014-01-01

    The catalytic cracking method of PAHs for the pyrolysis gaseous products is proposed to control their pollution to the environment. In this study, the Py-GC-MS is used to investigate in situ the catalytic effect of CaO and Fe2O3 on the 16 PAHs from Pingshuo coal pyrolysis under different catalytic temperatures and catalyst particle sizes. The results demonstrate that Fe2O3 is effective than that of CaO for catalytic cracking of 16 PAHs and that their catalytic temperature corresponding to the maximum PAHs cracking rates is different. The PAHs cracking rate is up to 60.59% for Fe2O3 at 600°C and is 52.88% at 700°C for CaO. The catalytic temperature and particle size of the catalysts have a significant effect on PAHs cracking rate and CaO will lose the capability of decreasing 16 PAHs when the temperature is higher than 900°C. The possible cracking process of 16 PAHs is deduced by elaborately analyzing the cracking effect of the two catalysts on 16 different species of PAHs. PMID:24963507

  9. Two years of gaseous emissions from contrasting soils amended with organic and synthetic nitrogen fertilizers.

    NASA Astrophysics Data System (ADS)

    Pelster, D. E.; Chantigny, M. H.; Rochette, P.; Angers, D. A.; Rieux, C.; Vanasse, A.

    2012-04-01

    Animal manures are often used as a source of nitrogen (N) for agriculture; however impacts of amendment type on N2O production may vary. In this study, N2O emissions from two soil types with contrasting texture and carbon (C) content (a silty clay mixed frigid dystric eutrudept and a sandy loam mixed frigid typic dystrudept) were measured for two years under a cool, humid climate. Treatments consisted of a no N control (CTL), calcium ammonium nitrate (CAN), poultry manure (PM), liquid cattle manure (LCM), or liquid swine manure (LSM). The N sources were surface applied and immediately incorporated at 90 kg N ha-1 before seeding of spring wheat (Triticum aestivum L.). Leaching losses of N were also measured using zero-tension lysimeters located at approximately 0.35 m depth. Cumulative growing season N2O-N emissions from the silty clay ranged from 2.2 to 8.3 kg ha-1 yr-1 and were slightly lower in CTL plots than in the fertilized plots (P = 0.067). The mean N2O emission factors ranged from 2.0 to 4.4% of added N with no difference among treatments. Emissions of N2O from the sandy loam soil ranged from 0.3 to 2.2 kg N2O-N ha-1 yr-1, with greatest emissions following PM application (P < 0.001). The N2O emission factor from sandy loam plots amended with PM was 1.7%, more than double that of the other treatments (0.3 to 0.9%), likely because of the high C content of the PM. On the silty clay the yield-based N2O emissions (g N2O-N kg-1 grain yield N) were similar between treatments; while on the sandy loam, they were greatest when amended with PM. Annual N leaching losses averaged 28.7 kg ha-1 for the silty clay and 19.6 kg ha-1 for the sandy loam and were similar for all amendment types suggesting that off-site N2O emissions will also be similar amongst treatments. Preliminary data indicate that overwinter N2O emissions from sandy loam plots were consistently greater when amended with pig slurry compared with unamended soils, and that these overwinter losses may exceed

  10. Air emission from the co-combustion of alternative derived fuels within cement plants: Gaseous pollutants.

    PubMed

    Richards, Glen; Agranovski, Igor E

    2015-02-01

    Cement manufacturing is a resource- and energy-intensive industry, utilizing 9% of global industrial energy use while releasing more than 5% of global carbon dioxide (CO₂) emissions. With an increasing demand of production set to double by 2050, so too will be its carbon footprint. However, Australian cement plants have great potential for energy savings and emission reductions through the substitution of combustion fuels with a proportion of alternative derived fuels (ADFs), namely, fuels derived from wastes. This paper presents the environmental emissions monitoring of 10 cement batching plants while under baseline and ADF operating conditions, and an assessment of parameters influencing combustion. The experiential runs included the varied substitution rates of seven waste streams and the monitoring of seven target pollutants. The co-combustion tests of waste oil, wood chips, wood chips and plastic, waste solvents, and shredded tires were shown to have the minimal influence when compared to baseline runs, or had significantly reduced the unit mass emission factor of pollutants. With an increasing ADF% substitution, monitoring identified there to be no subsequent emission effects and that key process parameters contributing to contaminant suppression include (1) precalciner and kiln fuel firing rate and residence time; (2) preheater and precalciner gas and material temperature; (3) rotary kiln flame temperature; (4) fuel-air ratio and percentage of excess oxygen; and (5) the rate of meal feed and rate of clinker produced. PMID:25947054

  11. Low emission characteristics of radiant burner

    SciTech Connect

    Bai, T.; Yeboah, Y.D.; Nie, J.X.; Wang, Z.; Shang, J.

    1998-12-31

    A commercial infrared burner is characterized in terms of its radiant efficiency and its emissions of CO, CO{sub 2}, O{sub 2}, unburned hydrocarbon, and NOx in the exhaust gases. It has been found that when methane is used as the fuel the burner reached its maximum radiation efficiency of 31.4% at the equivalence ratio {Phi} = 1. CO{sub 2} also reached its maximum value of 10.7% at {Phi} = 1. In the fuel-lean region, the concentrations of CO and unburned total hydrocarbon (UHC) were kept in a couple of hundred ppm ranges. In fuel-rich region, the CO and UHC concentrations quickly jumped to thousands of ppm or more as {Phi} increased. The NOx formation was strongly dependent on the equivalence ratio at which the burner was operated. The NOx reached its maximum of 8 ppm at {Phi} = 1, which was significantly lower than those from traditional gas burners. The NOx decreased significantly as the burner was operated at conditions away from stoichiometric. Tests were also conducted with fuel mixtures of methane and propane, which represented peak-saving gas in the industry. To simulate possible flash back, fuel mixture of methane and hydrogen was tested. Results from these tests provided insight into the effects of gas composition variations upon the IR burner performance characteristics. It has been found that the addition of propane in the fuel produced a higher combustion temperature and higher levels of NOx emission. It was also revealed by the test results that the addition of hydrogen to the methane fuel did not significantly affect the production of NOx, CO{sub 2} and CO.

  12. Earthworm effects on gaseous emissions during vermifiltration of pig fresh slurry.

    PubMed

    Luth; Robin, Paul; Germain, Philippe; Lecomte, Marcel; Landrain, Brigitte; Li, Yinsheng; Cluzeau, Daniel

    2011-02-01

    Treatment of liquid manure can result in the production of ammonia, nitrous oxide and methane. Earthworms mix and transform nitrogen and carbon without consuming additional energy. The objective of this paper is to analyse whether earthworms modify the emissions of NH(3), N(2)O, CH(4) and CO(2) during vermifiltration of pig slurry. The experiment used mesocosms of around 50 L, made from a vermifilter treating the diluted manure of a swine house. Three levels of slurry were added to the mesocosms, with or without earthworms, during one month, in triplicate. Earthworm abundance and gas emissions were measured three and five times, respectively. There was a decrease in emissions of ammonia and nitrous oxide and a sink of methane in treatments with earthworms. We suggest that earthworm abundance can be used as a bioindicator of low energy input, and low greenhouse gas and ammonia output in systems using fresh slurry with water recycling. PMID:21185175

  13. Gaseous exhaust emissions from a J-58 engine at simulated supersonic flight conditions

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.

    1974-01-01

    Emissions of total oxides of nitrogen, unburned hydrocarbons, carbon monoxide, and carbon dioxide from a J-58 engine at simulated flight conditions of Mach 2.0, 2.4, and 2.8 at 19.8 km altitude are reported. For each flight condition, measurements were made for four engine power levels from maximum power without afterburning through maximum afterburning. These measurements were made 7 cm downstream of the engine primary nozzle using a single point traversing gas sample probe. Results show that emissions vary with flight speed, engine power level, and with radial position across the exhaust.

  14. Relating summer ambient particulate sulfur, sulfur dioxide, and light scattering to gaseous tracer emissions from the MOHAVE Power Project.

    PubMed

    Mirabella, V A; Farber, R J

    2000-05-01

    Project MOHAVE was initiated in 1992 to examine the role of emissions from the 1580 MW coal-fired MOHAVE Power Project (MPP) on haze at the Grand Canyon National Park (GCNP), located about 130 km north-north-east of the power plant. Statistical relationships were analyzed between summertime ambient concentrations of a gaseous perfluorocarbon tracer released from MPP and ambient SO2, particulate sulfur, and light scattering to evaluate whether MPP's emissions could be transported to the GCNP and then impact haze levels there. Spatial analyses indicated that particulate sulfur levels were strongly correlated across the monitoring network, regardless of whether the monitoring stations were upwind or downwind of MPP. This indicates that particulate sulfur levels in this region were influenced by distant regional emission sources. A significant particulate sulfur contribution from a point source such as MPP would result in a non-uniform pattern downwind. There was no suggestion of this in the data. Furthermore, correlations between the MPP tracer and ambient particulate sulfur and light scattering at locations in the park were virtually zero for averaging times ranging from 24 hr to 1 hr. Hour-by-hour MPP tracer levels and light scattering were individually examined, and still no positive correlations were detected. Finally, agreement between tracer and particulate sulfur did not improve as a function of meteorological regime, implying that, even during cloudy monsoon days when more rapid conversion of SO2 to particulate sulfur would be expected, there was no evidence for downwind particulate sulfur impacts. Despite the fact that MPP was a large source of SO2 and tracer, neither time series nor correlation analyses were able to detect any meaningful relationship between MPP's SO2 and tracer emission "signals" to particulate sulfur or light scattering. PMID:10842939

  15. Theoretical and experimental investigation of plasma antenna characteristics on the basis of gaseous collisionality and electron density

    NASA Astrophysics Data System (ADS)

    Naito, Teruki; Yamaura, Shingo; Yamamoto, Kazuo; Tanaka, Tai; Chiba, Hidetoshi; Ogino, Hayato; Takahagi, Kazuhiro; Kitagawa, Shinya; Taniguchi, Daiki

    2015-01-01

    This paper reports plasma antenna characteristics investigated theoretically and experimentally, on the basis of the plasma parameters: gaseous collisionality and electron density. The antenna structure is a basic quarter-wavelength monopole antenna in the UHF band. The dependence of the antenna gain on the plasma parameters is obtained by analytical equations from plasma and antenna theory, and by numerical simulations. In the plasma antenna, the ratio of the electron elastic collision frequency to the total number of electrons at the plasma cross section determines the antenna’s internal loss and the electrical equivalent antenna length, whereas the ratio of the radio wave frequency to the total number of electrons at the plasma cross section determines the antenna’s resonant frequency. These results are confirmed by experimental results of the antenna’s impedance and radiation patterns.

  16. 40 CFR 87.64 - Sampling and analytical procedures for measuring gaseous exhaust emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ICAO Annex 16 (incorporated by reference in § 87.8). (b) Starting January 1, 2011, report CO2 values.... By January 1, 2011, report CO2 values along with your emission levels of regulated NOX to the... the individual engine was before January 1, 2011. Round CO2 to the nearest 1 g/kilonewton rO....

  17. Effects of oxygenated drinking water on gaseous emissions, rumen microorganisms and milk production in dairy cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dairy cattle production systems contribute to greenhouse gas emissions, predominantly in the form of methane. Enteric methane is formed by methanogenic archaea (methanogens) that require anaerobic conditions to thrive. A water treatment system (Oxion, Hugoton, KS) increases the dissolved oxygen conc...

  18. Effect of different struvite crystallization methods on gaseous emission and the comprehensive comparison during the composting.

    PubMed

    Jiang, Tao; Ma, Xuguang; Yang, Juan; Tang, Qiong; Yi, Zhigang; Chen, Maoxia; Li, Guoxue

    2016-10-01

    This study compared 4 different struvite crystallization process (SCP) during the composting of pig feces. Four combinations of magnesium and phosphate salts (H3PO4+MgO (PMO), KH2PO4+MgSO4 (KPM), Ca(H2PO4)2+MgSO4 (CaPM), H3PO4+MgSO4 (PMS)) were assessed and were also compared to a control group (CK) without additives. The magnesium and phosphate salts were all supplemented at a level equivalent to 15% of the initial nitrogen content on a molar basis. The SCP significantly reduced NH3 emission by 50.7-81.8%, but not the N2O. Although PMS group had the lowest NH3 emission rate, the PMO treatment had the highest struvite content in the end product. The addition of sulphate decreased CH4 emission by 60.8-74.6%. The CaPM treatment significantly decreased NH3 (59.2%) and CH4 (64.9%) emission and yielded compost that was completely matured. Due to its effective performance and low cost, the CaPM was suggested to be used in practice. PMID:26927235

  19. 40 CFR 87.64 - Sampling and analytical procedures for measuring gaseous exhaust emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ICAO Annex 16 (incorporated by reference in § 87.8). (b) Starting January 1, 2011, report CO2 values.... By January 1, 2011, report CO2 values along with your emission levels of regulated NOX to the... the individual engine was before January 1, 2011. Round CO2 to the nearest 1 g/kilonewton rO....

  20. 40 CFR 62.15175 - What continuous emission monitoring systems must I install for gaseous pollutants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... emission monitoring system according to the “Monitoring Requirements” in § 60.13 of subpart A of 40 CFR... subpart A of 40 CFR part 60. ... to use an alternative sulfur dioxide monitoring method, such as parametric monitoring, or...

  1. GASEOUS HC1 AND CHLORINATED ORGANIC COMPOUND EMISSIONS FROM REFUSE FIRED WASTE-TO-ENERGY SYSTEMS

    EPA Science Inventory

    The emissions from a water wall mass fired municipal waste incinerator and a refuse derived fuel (RDF) fired incinerator were sampled for chlorinated organic compounds and hydrochloric acid (HCl). The sampling was performed to evaluate the extractive sampling methods used to meas...

  2. DEVELOPMENT OF A TEST METHOD FOR THE MEASUREMENT OF GASEOUS METHANOL EMISSIONS FROM STATIONARY SOURCES

    EPA Science Inventory

    Methanol was designated under Title III of the Clean Air Act Amendments of 1990 as a pollutant to be regulated. he U.S. EPA, through a contract with Research Triangle Institute, has developed a test method for the measurement of methanol emissions from stationary sources. he meth...

  3. [Variation Characteristics of Total Gaseous Mercury at Simian Mountain Background Station in Mid-subtropical Region].

    PubMed

    Liu, Wei-ming; Ma, Ming; Wang, Ding-yong; Sun, Tao; Wei, Shi-qiang

    2016-05-15

    Total gaseous mercury (TGM) was continuously monitored at the Simian Mountain Forest Nature Reserve in Chongqing, a representative of the mid-subtropical region, using high-resolution automatic atmospheric mercury vapor analyzer (Tekran 2537X) from March 2012 to February 2013. The results showed that the average concentration of TGM during the monitoring was (2.88 ± 1.54) ng · m⁻³, which was much higher than the background TGM on north hemisphere but lower than those at most of the other monitoring sites in China. These results suggested that the TGM level in Simian Mountain was still in the normal range on regional scale, but had an increasing tendency globally. The TGM level exhibited a distinct seasonal variation, following the order of winter (3.68 ± 2.43) ng · m⁻³ > summer (3.29 ± 0.79) ng · m⁻³ > spring (2.44 ± 0.69) ng · m⁻³ > autumn (2.13 ± 0.97) ng · m⁻³, and the TGM concentration varied to a greater extent in winter. The diurnal variation of TGM concentration characterized as being higher at the nighttime in spring, while higher during the daytime in other seasons. The concentration variation of TGM had a positive correlation to temperature and light intensity. The result of backward trajectory analysis using HYSPLIT showed that the main source of the TGM in Simian Mountain was the local coal combustion, and long distance transportation by the Indian monsoon might also play a role in the increasing TGM level. PMID:27506014

  4. Risk assessment of an old landfill regarding the potential of gaseous emissions--a case study based on bioindication, FT-IR spectroscopy and thermal analysis.

    PubMed

    Tintner, Johannes; Smidt, Ena; Böhm, Katharina; Matiasch, Lydia

    2012-12-01

    Risk assessment of two sections (I and II) of an old landfill (ALH) in Styria (Austria) in terms of reactivity of waste organic matter and the related potential of gaseous emissions was performed using conventional parameters and innovative tools to verify their effectiveness in practice. The ecological survey of the established vegetation at the landfill surface (plant sociological relevés) indicated no relevant emissions over a longer period of time. Statistical evaluation of conventional parameters reveals that dissolved organic carbon (DOC), respiration activity (RA(4)), loss of ignition (LOI) and total inorganic carbon (TIC) mostly influence the variability of the gas generation sum (GS(21)). According to Fourier Transform Infrared (FT-IR) spectral data and the results of the classification model the reactivity potential of the investigated sections is very low which is in accordance with the results of plant sociological relevés and biological tests. The interpretation of specific regions in the FT-IR spectra was changed and adapted to material characteristics. Contrary to mechanically-biologically treated (MBT) materials, where strong aliphatic methylene bands indicate reactivity, they are rather assigned to the C-H vibrations of plastics in old landfill materials. This assumption was confirmed by thermal analysis and the characteristic heat flow profile of plastics containing landfill samples. Therefore organic carbon contents are relatively high compared to other stable landfills as shown by a prediction model for TOC contents based on heat flow profiles and partial least squares regression (PLS-R). The stability of the landfill samples, expressed by the relation of CO(2) release and enthalpies, was compared to unreactive landfills, archeological samples, earthlike materials and hardly degradable organic matter. Due to the material composition and the aging process the landfill samples are located between hardly degradable, but easily combustible

  5. Microwave remediation of electronic circuitry waste and the resulting gaseous emissions

    NASA Astrophysics Data System (ADS)

    Schulz, Rebecca L.

    The global community has become increasingly dependent on computer and electronic technology. As a result, society is faced with an increasing amount of obsolete equipment and electronic circuitry waste. Electronic waste is generally disposed of in landfills. While convenient, this action causes a substantial loss of finite resources and poses an environmental threat as the circuit board components breakdown and are exposed to the elements. Hazardous compounds such as lead, mercury and cadmium may leach from the circuitry and find their way into the groundwater supply. For this dissertation, a microwave waste remediation system was developed. The system was designed to remove the organic components from a wide variety of electronic circuitry. Upon additional heating of the resulting ash material in an industrial microwave, a glass and metal product can be recovered. Analysis of the metal reveals the presence of precious metals (gold, silver) that can be sold to provide a return on investment. a glass and metal product can be recovered. Analysis of the metal reveals the presence of precious metals (gold, silver) that can be sold to provide a return on investment. Gaseous organic compounds that were generated as a result of organic removal were treated in a microwave off gas system that effectively reduced the concentration of the products emitted by several orders of magnitude, and in some cases completely destroying the waste gas. Upon further heating in an industrial microwave, a glass and metal product were recovered. In order to better understand the effects of processing parameters on the efficiency of the off-gas system, a parametric study was developed. The study tested the microwave system at 3 flow rates (10, 30, and 50 ft 3/min) and three temperatures (400, 700 and 1000°C. In order to test the effects of microwave energy, the experiments were repeated using a conventional furnace. While microwave energy is widely used, the mechanisms of interaction with

  6. Evolution versus cooling of gaseous volcanic emissions from Momotombo Volcano, Nicaragua: Thermochemical model and observations

    NASA Astrophysics Data System (ADS)

    Quisefit, J. P.; Toutain, J. P.; Bergametti, G.; Javoy, M.; Cheynet, B.; Person, A.

    1989-10-01

    In order to identify the chemical reactions controlling the condensation of a high temperature volcanic gas phase, we have collected and analysed the various gas-related products of Momotombo Volcano, Nicaragua (high temperature gases, water condensates, silica tube sublimates, natural incrustations and aerosols) and the results were then compared with a thermochemical model of the behaviour of 29 major, minor and trace elements (H, B, C, N, O, F, Na, Mg, Al, Si, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, As, Se, Br, Pb, Mo, Sb, Sn, Ag, Au and Cd) under cooling. Theoretical mineral assemblages were then compared to the experimental results. The elemental composition of the starting gas phase (major, minor and trace elements) is in good agreement with previous studies of the Momotombo Volcano. Moreover, this gas was very close to thermodynamic equilibrium under the sampling conditions. Various mineral assemblages are observed in silica tubes sublimates, the distribution of which can be related to the temperature gradient. Most of them (mainly sylvite, halite, magnetite, molybdenite, pyrite, sulfosalts of As, Pb, Se and native sulfur) show good agreement with theoretical results with respect to both their nature and condensation temperature range. On the contrary, the occurrence of some sulfates in the tubes conflicts with the predictions of the model and is attributed to partial contamination by atmospheric oxygen of the gas in the sampling tubes. Conversely, some theoretical compounds were not detected in the tubes. The presence of solid S and H3BO3 in the low temperature fumarolic incrustations is consistent with the model, but not that of gypsum. This discrepancy may be due to their gaseous and metasomatic origin, respectively. Most of the observed crystal morphologies indicate condensation mechanisms occurring under conditions close to thermodynamic equilibrium. However, disequilibria were observed for some species. For instance, the formation of silica results, in part

  7. Uncontrolled combustion of shredded tires in a landfill – Part 1: Characterization of gaseous and particulate emissions

    PubMed Central

    Downard, Jared; Singh, Ashish; Bullard, Robert; Jayarathne, Thilina; Rathnayake, Chathurika; Simmons, Donald L.; Wels, Brian R.; Spak, Scott N.; Peters, Thomas; Beardsley, Douglas; Stanier, Charles; Stone, Elizabeth A.

    2014-01-01

    In summer 2012, a landfill liner comprising an estimated 1.3 million shredded tires burned in Iowa City, Iowa. During the fire, continuous monitoring and laboratory measurements were used to characterize the gaseous and particulate emissions and to provide new insights into the qualitative nature of the smoke and the quantity of pollutants emitted. Significant enrichments in ambient concentrations of CO, CO2, SO2, particle number (PN), fine particulate (PM2.5) mass, elemental carbon (EC), and polycyclic aromatic hydrocarbons (PAH) were observed. For the first time, PM2.5 from tire combustion was shown to contain PAH with nitrogen heteroatoms (a.k.a. azaarenes) and picene, a compound previously suggested to be unique to coal-burning. Despite prior laboratory studies’ findings, metals used in manufacturing tires (i.e. Zn, Pb, Fe) were not detected in coarse particulate matter (PM10) at a distance of 4.2 km downwind. Ambient measurements were used to derive the first in situ fuel-based emission factors (EF) for the uncontrolled open burning of tires, revealing substantial emissions of SO2 (7.1 g kg−1), particle number (3.5×1016 kg−1), PM2.5 (5.3 g kg−1), EC (2.37 g kg−1), and 19 individual PAH (totaling 56 mg kg−1). A large degree of variability was observed in day-to-day EF, reflecting a range of flaming and smoldering conditions of the large-scale fire, for which the modified combustion efficiency ranged from 0.85-0.98. Recommendations for future research on this under-characterized source are also provided. PMID:25663800

  8. Pilot scale facility to determine gaseous emissions from livestock slurry during storage.

    PubMed

    Petersen, Søren O; Skov, Morten; Drøscher, Per; Adamsen, Anders P S

    2009-01-01

    Livestock production is a growing source of air pollution, locally and to the wider environment. Improved livestock manure management has the potential to reduce environmental impacts, but there is a need for methodologies to precisely quantify emissions. This paper describes and evaluates a novel storage facility for livestock slurry consisting of eight 6.5-m(3) cylindrical units. The stores may be equipped with airtight covers and ventilated during storage or during measurement only. Each store has eight air inlets (160 mm diameter) and a single outlet in the cover connected to a main ventilation duct. The stores can also be used as static enclosures. Ventilation can be regulated within the range of 50 to 250 m(3) h(-1). A gas sampling line enables sampling of odorants using automatic thermal desorption tubes, ammonia using acid traps, and greenhouse gases using gas sampling bags (pooled samples) or a syringe (time point samples). Complete recovery of CH(4) independent of ventilation rate was demonstrated. Vertical profiles of CO(2) and CH(4) above the slurry surface with and without ventilation and mixing of the headspace indicated methane oxidation activity in the surface crust. p-Cresol and 4-ethyl phenol emission from pig slurry was identified by GC-MS analysis of odor collected on adsorption tubes. Ammonia emissions between 0 and 166 mg N m(-2) h(-1) were observed during storage of pig slurry with and without surface crust and cover. A comparison of pooled and averaged time point measurements of CO(2), CH(4), and N(2)O indicated that pooled samples account for the diurnal variations under realistic storage conditions. PMID:19549932

  9. Emission lines of [K v] in the optical spectra of gaseous nebulae

    PubMed Central

    Keenan, Francis P.; Aller, Lawrence H.; Espey, Brian R.; Exter, Katrina M.; Hyung, Siek; Keenan, Michael T. C.; Pollacco, Don L.; Ryans, Robert S. I.

    2002-01-01

    Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 Å)/I(4163.3 Å) as a function of electron density (Ne). This ratio is found to be very sensitive to changes in Ne over the density range 103 to 106 cm−3, but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical Ne diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo–Australian Telescope, reveals that the [K v] 4122.6 Å line in this object is badly blended with Fe ii 4122.6 Å. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum. PMID:11904366

  10. Emission lines of [K V] in the optical spectra of gaseous nebulae.

    PubMed

    Keenan, Francis P; Aller, Lawrence H; Espey, Brian R; Exter, Katrina M; Hyung, Siek; Keenan, Michael T C; Pollacco, Don L; Ryans, Robert S I

    2002-04-01

    Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 A)/I(4163.3 A) as a function of electron density (N(e)). This ratio is found to be very sensitive to changes in N(e) over the density range 10(3) to 10(6) cm(-3), but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical N(e) diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope, reveals that the [K v] 4122.6 A line in this object is badly blended with Fe ii 4122.6 A. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum. PMID:11904366

  11. Microwave emission characteristics of sea ice

    NASA Technical Reports Server (NTRS)

    Edgerton, A. T.; Poe, G.

    1972-01-01

    A general classification is presented for sea ice brightness temperatures with categories of high and low emission, corresponding to young and weathered sea ice, respectively. A sea ice emission model was developed which allows variations of ice salinity and temperature in directions perpendicular to the ice surface.

  12. X-ray absorption/emission line spectroscopy of the Galactic hot gaseous halo

    NASA Astrophysics Data System (ADS)

    Wang, Daniel

    2016-04-01

    There is an ongoing debate as to whether or not the Milky Way is surrounded by a large-scale, massive corona. Vastly different conclusions as to its extent and mass have been drawn from existing studies based on X-ray absorption and/or emission line spectroscopy. I will discuss my assessment of this issue, focusing on various uncertainties and potential problems in the present data, analyses, results, and interpretations.In particular, I will examine how different assumptions about the temperature distribution of the corona affect the inference of its physical scale. I will also discuss the external perspectives of galactic coronae obtained form observing nearby highly-inclined disk galaxies.

  13. Emission spectra of the cations of some fluoro-substituted phenols in the gaseous phase

    USGS Publications Warehouse

    Maier, John Paul; Marthaler, O.; Mohraz, Manijeh; Shiley, R.H.

    1980-01-01

    Emission spectra of the cations of 2,5- and 3,5-difluorophenol, of 2,3,4- and 2,4,5-trifluorophenol, of 2,3,5,6-tetrafluorophenol and of 2,3,4,5,6-pentafluorophenol have been obtained in the gas phase using low-energy electron beam excitation. The band systems are assigned to the B??(??-1) ??? X??(??-1) electronic transitions of these cations by reference to photoelectron spectroscopic data. The He(I??) photoelectron spectra and the ionisation energies of ten fluoro-substituted phenols are reported. The symmetries of the four lowest electronic states of these cations are inferred from the radiative decay studies. The lifetimes of the lowest vibrational levels of the B??(??-1) state of the six fluoro-substituted phenol cations above have also been measured. ?? 1980.

  14. Multi-Temperature Emission and Abundances in the Hot Gaseous Halo

    NASA Technical Reports Server (NTRS)

    Kim, Dong-Woo; Mushotzky, Richard F. (Technical Monitor)

    2003-01-01

    We present the results of XMM-Newton observations of NGC 507, a dominant elliptical galaxy in a small group of galaxies. After carefully considering various systematic effects on abundance measurements, we report 'super-solar' metal abundances (both Fe and a-elements) present in the hot ISM: ZFe = 2-3 times solar with an observational limit of as high as 4 times solar inside the D25 ellipse of NGC 507. This is the highest ZFe reported so far, and fully consistent with those expected by the stellar evolution models where heavy elements are enriched by both type II and Ia supernovae ejecta. No unusual constraint either on the SNe rate or IMF is required. Among various factors affecting the accurate abundance measurement, we find that selecting a proper emission model is most important. As opposed to the X-ray spectral data with limited s/n and poor spatial/spectral resolution obtained in the previous missions, the spatially resolved XMM spectra provide enough statistics to untie the model-Z degeneracy and statistically require at least 3 emission components in each concentric shell (2 thermal components representing a finite range of kT in the hot ISM + 1 hard LMXB component). We show that a simpler model (such as a two-component model) produce a much lower best-fit ZFe. The abundances of a-elements (most accurately determined by Si) is also found to be super-solar and its radio to Fe is close to the solar ratio, suggesting a considerably contribution of heavy elements from Type Ia SNe. We estimate approx. 70% of MFe in the hot ISM originate from Type Ia.

  15. Quantifying Total and Reactive Gaseous Mercury Emissions from the Sulphur Bank Mercury Mine Superfund Site, Northern California

    NASA Astrophysics Data System (ADS)

    Nacht, D. M.; Gustin, M. S.; Engle, M. A.; Zehner, R. E.; Giglini, A. D.

    2001-12-01

    Although it is generally assumed that elemental mercury is the dominant form of mercury (Hg) in the atmosphere, small amounts of Reactive Gaseous Mercury (RGM) have been measured. RGM species are at least 105 times more water soluble, more chemically reactive, and exhibit far greater wet and dry deposition rates than elemental mercury. This study evaluated mercury fluxes to the atmosphere and RGM concentrations at the Sulfur Bank Mercury Mine Superfund Site. Mercury emissions were measured from 17 sites on the Sulfur Bank Mercury Mine property and 6 locations offsite. Measured mercury fluxes ranged from 14 to 6895 ng m-2 hr-1 and were correlated with substrate mercury concentrations. RGM concentrations were measured with annular denuders at 8 sites on the Sulfur Bank Mercury Mine property and 2 locations offsite. RGM concentrations measured over the background Franciscan Sediments, during the day, ranged from 0.49 to 0.73 ng m-3, while concentrations measured over tailings, during the day, ranged from 1.79 to 75.88 ng m-3. RGM concentrations, measured during three week long sampling trips, ranged from ~ 0.03 to 70.76 % of total Hg concentrations with the highest percentage measured over the waste rock dam and in hydrothermally active areas. In a comparison of the use of annular versus tubular denuders for the measurement of RGM, it was found that they gave similar concentrations however annular denuders yielded less variability. Two Geographic Information System models were used to estimate mercury emissions from the SBMM site. These two models gave a range of 4.2 to 9.4 kg Hg yr-1.

  16. N IV emission lines in the ultraviolet spectra of gaseous nebulae

    NASA Technical Reports Server (NTRS)

    Keenan, F. P.; Ramsbottom, C. A.; Bell, K. L.; Berrington, K. A.; Hibbert, A.; Feibelman, W. A.; Blair, W. P.

    1995-01-01

    Theoretical electron density sensitive emission-line ratios, determined using electron impact excitation rates calculated with the R-matrix code, are presented for R = I(2s(sup 2) (1)S-2s2p 3P(sub 2))/I(2s(sup 2) (1)S-2s2p 3P(sub 1) = 1(1483 A)/I(1486 A) in N IV. These are found to be up to an order of magnitude different from those deduced by previous authors, principally due to the inclusion of excitation rates for transitions among the 2s2p (3)p fine-structure levels. The observed values of R for several planetary nebulae, symbiotic stars and the Cygnus Loop supernova remnant, measured from spectra obtained with the International Ultraviolet Explorer (IUE) satellite and the Hopkins Ultraviolet Explorer (HUT), lead to electron densities which are in excellent agreement with those deduced from line ratios in other species. This provides observational support for the accuracy of the atomic data adopted in the present calculations.

  17. Development of a test method for the measurement of gaseous methanol emissions from stationary sources

    SciTech Connect

    Pate, B.A.; Peterson, M.R.; Jayanty, R.K.M.; Wilshire, F.W.; Knoll, J.E.

    1993-01-01

    Methanol was designated under Title III of the Clean Air Act Amendments of 1990 as a pollutant to be regulated. The U.S. EPA, through a contract with Research Triangle Institute, has developed a test method for the measurement of methanol emissions from stationary sources. The methanol sampling train (MST) consists of a glass-lined heated probe, two knockout traps and three sorbent cartridges packed with Anasorb 747, a beaded, activated carbon. Anasorb 747 samples are desorbed with a 1:1 mixture of carbon disulfide and N,N-dimethylformamide. Samples are analyzed by gas chromatography with flame ionization detection. Following laboratory testing, field tests of the MST and the National Council for Air and Stream Improvement (NCASI) sampling method for methanol were conducted at a paper and pulp mill. The sampling location was an inlet vent to a softwood bleach plant scrubber. In accordance with EPA Method 301, two pairs of trains were run in parallel for six runs, collecting a total of twenty-four samples by each method.

  18. Detection of industrial gaseous chemical plumes using hyperspectral imagery in the emissive regime

    NASA Astrophysics Data System (ADS)

    Farrell, Michael D., Jr.; Mersereau, Russell M.

    2005-08-01

    For the past ten years, much of the research in hyperspectral image data exploitation techniques has been focused on detection of ground targets. As a passive remote sensing technique, hyperspectral imagers have performed reasonably well in detecting the presence of a variety of objects; from crop species to land mines to mineral deposits to vehicles under camouflage. These often promising results have prompted new studies of hyperspectral remote sensing for other applications - including atmospheric monitoring. Should technologies like hyperspectral imaging prove effective in emission source monitoring, organizations interested in environmental assessment could transition from inspection using hand-held analytical instruments to a truly standoff technique. In this paper, we evaluate the utility of a set of hyperspectral exploitation techniques applied to the task of gas detection. This set of techniques is a sampling of approaches that have appeared in the literature, and all of the methods discussed have demonstrated utility in the reflective regime. Specifically, we look at signature-based detection, anomaly detection, transformations (i.e. rotations) of the spectral space, and even dedicated band combinations and scatter plots. Using real LWIR hyperspectral data recently collected on behalf of the US Environmental Protection Agency, we compare performance in detecting three different industrial gases.

  19. Oxidation characteristics of 440 C CRES in gaseous oxygen (GOX) environments. [Corrosion Resistant Steel

    SciTech Connect

    Dennies, D.P.; Parsons, T.D.

    1986-10-01

    The oxidation characteristics of 440 C corrosion-resistant steel are evaluated. The dependence of oxide color, type, and thickness, material hardness, and microstructure on temperature is examined. The effects of exposure time, passivation layer, and oxygen pressure on the oxide formation are investigated. A direct relationship between temperature and oxide color, formation, and thickness is detected. It is observed that the exposure time does not affect the microstructure or oxide color, type, or thickness; however, the passivation layer does affect oxide color and type. 9 references.

  20. Oxidation characteristics of 440 C CRES in gaseous oxygen (GOX) environments. [Corrosion Resistant Steel

    NASA Technical Reports Server (NTRS)

    Dennies, Daniel P.; Parsons, Terry D.

    1986-01-01

    The oxidation characteristics of 440 C corrosion-resistant steel are evaluated. The dependence of oxide color, type, and thickness, material hardness, and microstructure on temperature is examined. The effects of exposure time, passivation layer, and oxygen pressure on the oxide formation are investigated. A direct relationship between temperature and oxide color, formation, and thickness is detected. It is observed that the exposure time does not affect the microstructure or oxide color, type, or thickness; however, the passivation layer does affect oxide color and type.

  1. Characteristics of total gaseous mercury (TGM) concentrations in an industrial complex in South Korea: impacts from local sources

    NASA Astrophysics Data System (ADS)

    Seo, Yong-Seok; Jeong, Seung-Pyo; Holsen, Thomas M.; Han, Young-Ji; Choi, Eunhwa; Park, Eun Ha; Kim, Tae Young; Eum, Hee-Sang; Park, Dae Gun; Kim, Eunhye; Kim, Soontae; Kim, Jeong-Hun; Choi, Jaewon; Yi, Seung-Muk

    2016-08-01

    Total gaseous mercury (TGM) concentrations were measured every 5 min in Pohang, Gyeongsangbuk-do, Korea, during summer (17-23 August 2012), fall (9-17 October 2012), winter (22-29 January 2013), and spring (26 March-3 April 2013) to (1) characterize the hourly and seasonal variations of atmospheric TGM concentrations; (2) identify the relationships between TGM and co-pollutants; and (3) identify likely source directions and locations of TGM using the conditional probability function (CPF), conditional bivariate probability function (CBPF) and total potential source contribution function (TPSCF). The TGM concentration was statistically significantly highest in fall (6.7 ± 6.4 ng m-3), followed by spring (4.8 ± 4.0 ng m-3), winter (4.5 ± 3.2 ng m-3) and summer (3.8 ± 3.9 ng m-3). There was a weak but statistically significant negative correlation between the TGM concentration and ambient air temperature (r = -0.08, p<0.05). Although the daytime temperature (14.7 ± 10.0 °C) was statistically significantly higher than that in the nighttime (13.0 ± 9.8 °C) (p<0.05), the daytime TGM concentration (5.3 ± 4.7 ng m-3) was statistically significantly higher than that in the nighttime (4.7 ± 4.7 ng m-3) (p<0.01), possibly due to local emissions related to industrial activities and activation of local surface emission sources. The observed ΔTGM / ΔCO was significantly lower than that of Asian long-range transport, but similar to that of local sources in Korea and in US industrial events, suggesting that local sources are more important than those of long-range transport. CPF, CBPF and TPSCF indicated that the main sources of TGM were iron and manufacturing facilities, the hazardous waste incinerators and the coastal areas.

  2. Evaluation of clay aggregate biotrickling filters for treatment of gaseous emissions from intensive pig production.

    PubMed

    Liu, Dezhao; Løkke, Mette Marie; Riis, Anders Leegaard; Mortensen, Knud; Feilberg, Anders

    2014-04-01

    Treatment of ventilation air from livestock production by biological airfiltration has emerged as a cost-effective technology for reduction of emissions of odorants and ammonia. Volatile sulfur compounds from livestock production include H2S and methanethiol, which have been identified as potentially important odorants that are not removed sufficiently by biological air filters. Light-expanded clay aggregates (Leca(®)) is a biotrickling filter material that contains iron oxides, which can oxidize H2S and methanethiol, and thus potentially may help to remove these two compounds in biological air filters. This study used on-line PTR-MS measurements to investigate the performances of two Leca(®) biotrickling filters (abraded Leca(®) filter and untreated Leca(®) filter) for removal of odorants and ammonia emitted from an experimental pig house. The results indicated that the abraded Leca(®) filter had a similar or slightly better capability for removing odorants than the untreated Leca(®) filter. This may be due to the enlargement of the surface area by the friction process. The volatile sulfur compounds, however, were not removed efficiently by either of the two Leca(®) filters. Kinetic analysis of a ventilation controlled experiment during the first period indicated that Grau second-order kinetics could be applied to analyze the removal of sulfur compounds and other odorants, whereas the Stover-Kincannon model could only be applied to analyze the removal of odorants other than sulfur compounds, partly due to the limitation of mass transfer of these compounds in the biotrickling filters. In the last measurement period, a production of dimethyl disulfide and dimethyltrisulfide coinciding with strongly enhanced removal of methanethiol was observed for the untreated filter. This was assumed to be enhanced by an incidence of low local air velocity in the filter and indicated involvement of iron-catalyzed reactions in the removal of sulfur compounds. PMID:24534901

  3. Direct detection of vacuum ultraviolet radiation through an optical sampling orifice: determination of nonmetals in gaseous samples by inductively coupled plasma atomic emission spectroscopy

    SciTech Connect

    LaFreniere, B.R.; Houk, R.S.; Wiederin, D.R.; Fassel, V.A.

    1988-01-01

    A copper cone with a sampling orifice is attached to the entrance slit chamber or a monochromator and inserted directly into an inductively couples plasma (ICP) to sample vacuum ultraviolet (vacuum UV) radiation emitted by the plasma. A unique interface with low dead volume (<40 ..mu..L) is used for introduction of gaseous samples directly into the axial channel of the ICP. Injection of a gaseous mixture of compounds containing the elements Br, C, Cl, and S results in detection limits of 50, 30, 80 and 20 pg, respectively. These detection limits are by far the best obtained for these elements by ICP atomic emission spectroscopy (AES) and are comparable to those obtained by AES with He plasmas. Precision of the analyte emission intensities is 2% relative standard deviation or better.

  4. Gaseous emissions during the fattening of pigs kept either on fully slatted floors or on straw flow.

    PubMed

    Philippe, F-X; Laitat, M; Canart, B; Vandenheede, M; Nicks, B

    2007-11-01

    The aim of this study was to compare the environmental impact of the straw-flow system for fattening pigs with the slatted-floor system by measuring pollutant gas emissions such as ammonia (NH3), nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2), manure nitrogen (N) content and emissions of water vapour (H2O). Three successive batches of 32 pigs were fattened. For each batch, pigs were allotted to two groups raised in separated rooms fitted either with a concrete totally slatted-floor system (0.75 m2 per pig) or with a straw-flow system (0.79 m2 per pig). With this last system, pigs were kept on a sloped floor, straw being provided daily at the top of the pen. Throughout the fattening period, about 34.4 kg of straw were supplied per pig. The straw, mixed with dung, travelled down the slope by pig motion and went out of the pen to a scraped passage. The solid fraction was scraped every day, stored in a heap in the room and removed every month, 1 week before each period of gaseous emission measurement. The liquid fraction was automatically pumped from the scraped passage into a hermetic tank, which was emptied at the end of each fattening period. Rooms were ventilated mechanically in order to maintain a constant ambient temperature. Once a month, the emissions of NH3, N2O, CH4, CO2 and H2O were measured hourly for 6 consecutive days via infrared photoacoustic detection. Mean daily emissions per pig fattened on the slatted floor or on the sloped floor were, respectively, 4.98 and 13.31 g NH3, 0.67 and 0.68 g N2O, 15.2 and 8.88 g CH4, 548 g and 406 g CO2 equivalents, 1.61 and 1.77 kg CO2 and 2.33 and 2.95 kg H2O. Except for N2O emissions, all the differences were statistically significant (P < 0.001). From the slatted-floor system, the amount of slurry removed per fattening period was on average 256 kg per pig. From the straw-flow system, solid manure amounted on average to 209 kg per pig and liquid manure to 53 kg per pig. The total N-content of the manure

  5. Measurements of admittances and characteristic combustion times of reactive gaseous propellant coaxial injectors

    NASA Technical Reports Server (NTRS)

    Janardan, B. A.; Daniel, B. R.; Zinn, B. T.

    1979-01-01

    The results of an experimental investigation that was concerned with the quantitative determination of the capabilities of combustion processes associated with coaxial injectors to amplify and sustain combustor oscillations was described. The driving provided by the combustion process was determined by employing the modified standing-wave method utilizing coaxial injectors and air-acetylene mixtures. Analyses of the measured data indicate that the investigated injectors are capable of initiating and amplifying combustion instabilities under favorable conditions of injector-combustion coupling and over certain frequency ranges. These frequency ranges and the frequency at which an injector's driving capacity is maximum are observed to depend upon the equivalence ratio, the pressure drop across the injector orifices and the number of injector elements. The characteristic combustion times of coaxial injectors were determined from steady state temperature measurements.

  6. Methane fueled engine performance and emissions characteristics

    SciTech Connect

    Swain, M.R.; Adt, R.R.; Bedsworth, K.; Maxwell, R.; Pappas, J.M.; Swain, M.N.

    1983-08-01

    A 1983 Ford 3.8 liter V-6 engine was fueled with methane and tested on an engine dynamometer in order to begin to generate a data base that could be used to estimate emission levels and fuel economy for a driving cycle from a 3-point mini map method. The results showed that, with the proper control of pertinent engine variables, the engine would probably meet the current State of California Emission Standards that have been formulated to account for methane as an unburned hydrocarbon, without having to resort to a catalytic converter, and with Joules fuel consumption comparable, if not better than that for a gasoline-fueled vehicle. Unburned fuel in the exhaust was found to be comprised of between 87 and 96% methane. MBTH total aldehyde emissions were found to vary between 27 and 67 molar ppm.

  7. Effects of available surface on gaseous emissions from group-housed gestating sows kept on deep litter.

    PubMed

    Philippe, F X; Canart, B; Laitat, M; Wavreille, J; Bartiaux-Thill, N; Nicks, B; Cabaraux, J F

    2010-10-01

    In the European Union, the group-housed pregnant sows have to have a minimal legal available area of 2.25 m2/sow. However, it has been observed that an increased space allowance reduces agonistic behaviour and consecutive wounds and thus induces better welfare conditions. But, what about the environmental impacts of this greater available area? Therefore, the aim of this study was to quantify pollutant gases emissions (nitrous oxide, N2O, methane, CH4, carbon dioxide, CO2 and ammonia, NH3), according to the space allowance in the raising of gestating sows group-housed on a straw-based deep litter. Four successive batches of 10 gestating sows were each divided into two homogeneous groups and randomly allocated to a treatment: 2.5 v. 3.0 m2/sow. The groups were separately kept in two identical rooms. A restricted conventional cereals based diet was provided once a day in individual feeding stalls available only during the feeding time. Rooms were automatically ventilated. The gas emissions were measured by infra red photoacoustic detection during six consecutive days at the 6th, 9th and 12th weeks of gestation. Sows performance (body weight gain, backfat thickness, number and weight of piglets) was not significantly different according to the space allowance. In the room with 3.0 m2/sow and compared with the room with 2.5 m2/sow, gaseous emissions were significantly greater for NH3 (6.29 v. 5.37 g NH3-N/day per sow; P < 0.01) and significantly lower for N2O (1.78 v. 2.48 g N2O-N/day per sow; P < 0.01), CH4 (10.15 v. 15.21 g/day per sow; P < 0.001), CO2 equivalents (1.11 v. 1.55 kg/day per sow; P < 0.001), CO2 (2.12 v. 2.41 kg/day per sow; P < 0.001) and H2O (3.10 v. 3.68 kg/day per sow; P < 0.001). In conclusion, an increase of the available area for group-housed gestating sow kept on straw-based deep litter seems to be ambiguous on an environmental impacts point of view. Compared with a conventional and legal available area, it favoured NH3 emissions, probably due

  8. Characteristics of real-world vehicular emissions in Chinese cities.

    PubMed

    Yao, Zhiliang; Wang, Qidong; He, Kebin; Huo, Hong; Ma, Yongliang; Zhang, Qiang

    2007-11-01

    On-board emission measurements were performed on 49 light-duty gasoline vehicles in seven cities of China. Vehicle-specific power mode distribution and emission characteristics were analyzed based on the data collected. The results of our study show that there were significant differences in different types of roads. The emission factors and fuel consumption rates on arterial roads and residential roads were approximately 1.4-2 times those on freeways. The carbon monoxide, hydrocarbon, and nitrogen oxides emission factors of Euro II vehicles were on average 86.2, 88.2, and 64.5% lower than those of carburetor vehicles, respectively. The new vehicle emission standards implemented in China had played an important role in reducing individual vehicle emissions. More comprehensive measures need to be considered to reduce the total amount of emissions from vehicles. PMID:18069461

  9. Nanodiamond vacuum field emission device with gate modulated triode characteristics

    NASA Astrophysics Data System (ADS)

    Hsu, S. H.; Kang, W. P.; Raina, S.; Huang, J. H.

    2013-05-01

    A three-electrode nanodiamond vacuum field emission (VFE) device with gate modulated triode characteristics is developed by integrating nanodiamond emitter with self-aligned silicon gate and anode, employing a mold transfer technique in conjunction with chemical vapor deposition of nanodiamond. Triode behavior showing emission current modulation with high current density at low operating voltages is achieved. A systematic analysis based on modified Fowler-Nordheim theory is used to analyze gate modulated VFE characteristics, confirming the triode field emission mechanism and operating principle. The realization of an efficient VFE microtriode has achieved the fundamental step for further development of vacuum integrated microelectronics.

  10. Extraction of internal emission characteristics from printed OLEDs

    NASA Astrophysics Data System (ADS)

    Hildner, Mark L.; Ziebarth, Jonathan M.

    2012-09-01

    Accurate optical modeling of OLED device performance is beneficial to OLED manufacturing because as materials and architectures are modified, experimental effort and resources are saved in the search for optimal structures. The success of such modeling depends crucially on model inputs, which include, along with layer thicknesses and optical constants, internal emission characteristics such as the internal emission spectrum (IES) of the emitter and the location and profile of emission in the emissive layer (EML). This presentation will describe two methods we have used to extract the internal emission characteristics of our printed bottom emitting OLEDs. The first method, which we devised and implemented with assumptions specific to our devices, is a simpler one for both modeling and data collection: we collected spectra at normal viewing angle for a series of devices with different architectures, and extracted a normalized IES common to all these devices. We will show how an emission location was obtained from this method with some simple model assumptions. In the more rigorous second method - one presented by van Mensfoort et al 1 - internal emission characteristics were extracted independently for each device: spectra at multiple angles were collected, which allowed the extraction of an individual IES and emission profile. We will compare the findings of the two methods and assess the validity of the assumptions used in the first method.

  11. [Characteristic of Particulate Emissions from Concrete Batching in Beijing].

    PubMed

    Xue, Yi-feng; Zhou, Zhen; Zhong, Lian-hong; Yan, Jing; Qu, Song; Huang, Yu-hu; Tian, He- zhong; Pan, Tao

    2016-01-15

    With the economic development and population growth in Beijing, there is a strong need for construction and housing, which leads to the increase of the construction areas. Meanwhile, as a local provided material, the production of concrete has been raised. In the process of concrete production by concrete batching, there are numerous particulates emitted, which have large effect on the atmospheric environment, however, systematic study about the tempo-spatial characteristics of pollutant emission from concrete batching is still rare. In this study, we estimated the emission of particulates from concrete batching from 1991 to 2012 using emission factor method, analyzed the tempo-spatial characteristics of pollutant emission, established the uncertainty range by adopting Monte-Carlo method, and predicted the future emission in 2020 based on the relative environmental and economical policies. The results showed that: (1) the emissions of particulates from concrete batching showed a trend of "first increase and then decrease", reaching the maximum in 2005, and then decreased due to stricter emission standard and enhanced environmental management. (2) according to spatial distribution, the emission of particulates from concrete batch mainly concentrated in the urban area with more human activities, and the area between the fifth ring and the sixth ring contributed the most. (3) through scenarios analysis, for further reducing the emission from concrete batching in 2020, more stricter standard for green production as well as powerful supervision is needed. PMID:27078945

  12. Influence of in-port ships emissions to gaseous atmospheric pollutants and to particulate matter of different sizes in a Mediterranean harbour in Italy

    NASA Astrophysics Data System (ADS)

    Merico, E.; Donateo, A.; Gambaro, A.; Cesari, D.; Gregoris, E.; Barbaro, E.; Dinoi, A.; Giovanelli, G.; Masieri, S.; Contini, D.

    2016-08-01

    Ship emissions are a growing concern, especially in coastal areas, for potential impacts on human health and climate. International mitigation strategies to curb these emission, based on low-sulphur content fuels, have proven useful to improve local air quality. However, the effect on climate forcing is less obvious. Detailed information on the influence of shipping to particles of different sizes is needed to investigate air quality and climate interaction. In this work, the contributions of maritime emissions to atmospheric concentrations of gaseous pollutants (NO, NO2, SO2, and O3) and of particles (sizes from 0.009 μm to 30 μm) were investigated considering manoeuvring (arrival and departure of ships) and hotelling phases (including loading/unloading activities). Results showed that the size distributions of shipping contributions were different for the two phases and could be efficiently described, using measured data, considering four size-ranges. The largest contribution to particles concentration was observed for Dp < 0.25 μm, however, a secondary maximum was observed at Dp = 0.35 μm. The minimum contribution was observed at Dp around 0.8-0.9 μm with a negligible contribution from hotelling for size range 0.4-1 μm. The comparison of 2012 and 2014 datasets showed no significant changes of gaseous and particulate pollutant emissions and of the contribution to particle mass concentration. However, an increase of the contribution to particle number concentration (PNC) was observed. Results suggested that harbour logistic has a relevant role in determining the total impact of shipping on air quality of the nearby coastal areas. Additionally, future policies should focus on PNC that represents an important fraction of emissions also for low-sulphur fuels. DOAS remote sensing proved a useful tool to directly measure NO2 and SO2 ship emissions giving estimates comparable with those of emission inventory approach.

  13. Fault structure, damage and acoustic emission characteristics

    NASA Astrophysics Data System (ADS)

    Dresen, G. H.; Göbel, T.; Stanchits, S.; Kwiatek, G.; Charalampidou, E. M.

    2011-12-01

    We investigate the evolution of faulting-related damage and acoustic emission activity in experiments performed on granite, quartzite and sandstone samples with 40-50 mm diameter and 100-125 mm length. Experiments were performed in a servo-controlled MTS loading frame in triaxial compression at confining pressures ranging from 20-140 MPa. We performed a series of fracture and stick-slip sliding experiments on prefractured samples. Acoustic emissions (AE) and ultrasonic velocities were monitored using up to 14 P-wave sensors glued to the cylindrical surface of the rock. Full waveforms were stored in a 16 channel transient recording system (Daxbox, PRÖKEL, Germany). Full moment tensor analysis and polarity of AE first motions were used to discriminate source types associated with tensile, shear and pore-collapse cracking. To monitor strain, two pairs of orthogonally oriented strain-gages were glued onto the specimen surface. Fracture nucleation and growth occurred from a nucleation patch mostly located at the specimen surface or at the tip of prefabricated notches inside the specimens. Irrespective of the rock type, fracture propagation is associated with formation of a damage zone surrounding the fracture surface as revealed by distribution of cracks and AE hypocenters displaying a logarithmic decay in microcrack damage with distance normal to the fault trace. The width of the damage zone varies along the fault. After fracturing, faults were locked by increasing confining pressure. Subsequent sliding was mostly induced by driving the piston at a constant displacement rate producing large single events or multiple stick-slips. With increasing sliding distance a corrugated and rough fault surface formed displaying displacement-parallel lineations. Microstructural analysis of fault surfaces and cross-sections revealed formation of multiple secondary shears progressively merging into an anastomosing 3D-network controlling damage evolution and AE activity in the fault

  14. Gaseous Nitrogen Losses from Tropical Savanna Soils of Northern Australia: Dynamics, Controls and Magnitude of N2O, NO, and N2 emissions

    NASA Astrophysics Data System (ADS)

    Werner, C.; Hickler, T.; Hutley, L. B.; Butterbach-Bahl, K.

    2014-12-01

    Tropical savanna covers a large fraction of the global land area and thus may have a substantial effect on the global soil-atmosphere exchange of nitrogen. The pronounced seasonality of hygric conditions in this ecosystem affects strongly microbial process rates in the soil. As these microbial processes control the uptake, production, and release of nitrogen compounds, it is thought that this seasonality finally leads to strong temporal dynamics and varying magnitudes of gaseous losses to the atmosphere. However, given their areal extent and in contrast to other ecosystems, still few in-situ or laboratory studies exist that assess the soil-atmosphere exchange of nitrogen. We present laboratory incubation results from intact soil cores obtained from a natural savanna site in Northern Australia, where N2O, NO, and N2 emissions under controlled environmental conditions were investigated. Furthermore, in-situ measurements of high temporal resolution at this site recorded with automated static and dynamic chamber systems are discussed (N2O, NO). This data is then used to assess the performance of a process-based biogeochemical model (LandscapeDNDC), and the potential magnitude and dynamics of components of the site-scale nitrogen cycle where no measurements exist (biological nitrogen fixation and nitrate leaching). Our incubation results show that severe nutrient limitation of the soil only allows for very low N2O emissions (0.12 kg N ha-1 yr-1) and even a periodic N2O uptake. Annual NO emissions were estimated at 0.68 kg N ha-1 yr-1, while the release of inert nitrogen (N2) was estimated at 6.75 kg N ha-1 yr-1 (data excl. contribution by pulse emissions). We observed only minor N2O pulse emissions after watering the soil cores and initial rain events of the dry to wet season transition in-situ, but short-lived NO pulse emissions were substantial. Interestingly, some cores exhibited a very different N2O emission potential, indicating a substantial spatial variability of

  15. Study of the microwave emissivity characteristics over Gobi Desert

    NASA Astrophysics Data System (ADS)

    Yubao, Qiu; Lijuan, Shi; Wenbo, Wu

    2014-03-01

    The microwave emissivity represents the capacity of the thermal radiation of the surface, and it is the significant parameter for understanding the geophysical processes such as surface energy budget and surface radiation. Different land covers have different emissivity properties, and the Gobi Desert in Central Asia seriously impact the sandstorms occur and develop in China, because of its special geographical environment and surface soil characteristics. In this study half-month averaged microwave emissivity from March 2003 to February 2004 over the Gobi Desert has been estimated. Emissivities in this area at different frequencies, polarization and their seasonal variations are discussed respectively. The results showed that emissivity polarization difference decrease as the frequency increases, and the polarization difference is large (0.03-0.127). The H polarization emissivity increases with increasing frequency, but the V-polarized microwave emissivity is reduced with increasing frequency because of the body scattering. In winter, emissivity decreases sharply in snow covered area, especially for higher frequencies (such as 89GHz). In addition, we compared emissivity with MODIS NDVI data at the same time in the Gobi Desert, and the results indicate that NDVI derived the good negative correlation with microwave emissivity polarization difference at 37GHz.

  16. Field Emission Characteristics of Polyaniline/Se Nanocomposites.

    PubMed

    Shumaila; Parveen, S; Alam, Masood; Siddiqui, Azher M; Husain, M

    2015-04-01

    Polyaniline (PAni)/Se nanocomposites have been synthesized in different compositions employing chemical route and shown excellent field emission behaviour. Detailed studies on the field emission for all composites with different concentrations of dopant are performed in an indigenously fabricated set up in a vacuum chamber with a base pressure of 10(-6) Torr at room temperature and analysed with current density versus Electric field (J-E) and Fowler-Nordheim (FN) plots. Comparative field emission results showed that 10% (w/w) doped PAni/Se nanocomposite depicts highest emission characteristics, current density and field enhancement factor with turn-on field as low as 1.2 V/µm in comparison with other composites, while pure PAni shows no field emission characteristics. These composites have also been characterized by Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometry (FTIR). FTIR results supply the evidence for the occurrence of the polymer in its conducting state. The ease of synthesis route and interesting field emission properties recommend these composites as a promising material for field emission based applications in vacuum micro-nanoelectronic devices and also for plastic display industry. PMID:26353501

  17. Odour emission characteristics of 22 recreational rivers in Nanjing.

    PubMed

    Wan, Yu; Ruan, Xiaohong; Wang, Xinguang; Ma, Qian; Lu, Xiaoming

    2014-10-01

    The odour emission characteristics of 22 recreational rivers in Nanjing were investigated and analysed. Eight odorous compounds (ammonia (NH₃), hydrogen sulphide (H₂S), sulphur dioxide (SO₂), carbon disulphide (CS₂), nitrobenzene (C₆H₅NO₂), aniline (C₆H₅NH₂), dimethylamine (C₂H₇N), and formaldehyde (HCHO)) were measured in odour emission samples collected using a custom-made emission flux hood chamber. The results showed that all odorants were detected in all monitoring rivers. NH₃ was the main odorant, with emission rates ranging from 4.86 to 15.13 μg/min m(2). The total odour emission rate of the Nan River, at 1 427.07 OU/s, was the highest of the all investigated rivers. H₂S, NH₃ and nitrobenzene were three key odour emission contributors according to their contributions to the total odour emission. A correlation analysis of the pollutants showed there was a significant positive correlation between the emission rate of NH₃ and the concentration of ammonia nitrogen (NH₄ (+)-N) and total nitrogen (TN). The H₂S and SO₂ emission rates had a significant positive correlation with sulphides (S(2-)) and available sulphur (AS) in the water and sediment. The content of TN, NH₄(+)-N, S(2-) and AS in the water and sediment affected the concentration of H₂S, SO₂ and NH₃ in the emission gases. NH₄(+)-N, S(2-) and AS are suggested as the key odour control indexes for reducing odours emitted from these recreational rivers. The study provides useful information for effective pollution control, especially for odour emission control for the recreational rivers of the city. It also provides a demonstrate example to show how to monitor and assess a contaminated river when odour emission and its control need to be focused on. PMID:24939710

  18. Estimation of exhaust and non-exhaust gaseous, particulate matter and air toxics emissions from on-road vehicles in Delhi

    NASA Astrophysics Data System (ADS)

    Nagpure, Ajay Singh; Gurjar, B. R.; Kumar, Vivek; Kumar, Prashant

    2016-02-01

    Analysis of emissions from on-road vehicles in an Indian megacity, Delhi, have been performed by comparing exhaust emissions of gaseous, particulate matter and mobile source air toxics (MSATs), together with volatile organic compound (VOCs) and PM10 (particulate matter ≤10 μm) from non-exhaust vehicular sources, during the past (1991-2011) and future (2011-2020) scenarios. Results indicate that emissions of most of the pollutants from private vehicles (two wheelers and cars) have increased by 2- to 18-times in 2020 over the 1991 levels. Two wheelers found to be dominating the emissions of carbon monoxide (CO, 29-51%), hydrocarbons (HC, 45-73%), acetaldehyde (46-51%) and total poly aromatic hydrocarbons (PAHs, 37-42%). Conversely, private cars were found to be responsible for the majority of the carbon dioxide (CO2, 24-42%), 1,3-butadiene (72-89%), benzene (60-82%), formaldehyde (23-44%) and total aldehyde (27-52%) between 1991 and 2011. The heavy-duty commercial vehicles (HCVs) shows their accountability for most of the nitrogen oxide (NOx, 18-41%) and PM10 (33-43%) emissions during the years 1991-2011. In terms of PM10 emissions, vehicular exhaust contributed by 21-55%, followed by road dust (42-73%) and brake wear (3-5%) between 1991 and 2011. After 2002, non-exhaust emissions (e.g. road dust, brake wear and tyre wear) together indicate higher accountability (66-86%) for PM10 emission than the exhaust emissions (14-34%). The temporal trend of emissions of NOx and CO show reasonable agreement with available ambient air concentrations that were monitored at locations, significantly influenced by vehicular activity. Encouraging results were emerged, showing a good correlation coefficient for CO (0.94) and NOx (0.68).

  19. A comprehensive emission inventory of multiple air pollutants from iron and steel industry in China: Temporal trends and spatial variation characteristics.

    PubMed

    Wang, Kun; Tian, Hezhong; Hua, Shenbing; Zhu, Chuanyong; Gao, Jiajia; Xue, Yifeng; Hao, Jiming; Wang, Yong; Zhou, Junrui

    2016-07-15

    China has become the largest producer of iron and steel throughout the world since 1996. However, as an energy-and-pollution intensive manufacturing sector, a detailed comprehensive emission inventory of air pollutants for iron and steel industry of China is still not available. To obtain and better understand the temporal trends and spatial variation characteristics of typical hazardous air pollutants (HAPs) emissions from iron and steel production in China, a comprehensive emission inventory of multiple air pollutants, including size segregated particulate matter (TSP/PM10/PM2.5), gaseous pollutants (SO2, NOx, CO), heavy metals (Pb, Cd, Hg, As, Cr, Ni etc.), as well as the more dangerous PCDD/Fs, is established with the unit-based annual activity, specific dynamic emission factors for the historical period of 1978-2011, and the future potential trends till to 2050 are forecasted by using scenario analysis. Our results show that emissions of gaseous pollutants and particulate matter have experienced a gradual increase tendency since 2000, while emissions of priority-controlled heavy metals (Hg, Pb, As, Cd, Cr, and Ni) have exhibited a short-term fluctuation during the period of 1990 to 2005. With regard to the spatial distribution of HAPs emissions in base year 2011, Bohai economic circle is identified as the top emission intensity region where iron and steel smelting plants are densely built; within iron and steel industry, blast furnaces contribute the majority of PM emissions, sinter plants account for most of gaseous pollutants and the majority of PCDD/Fs, whereas steel making processes are responsible for the majority of heavy metal emissions. Moreover, comparisons of future emission trends under three scenarios indicate that advanced technologies and integrated whole process management strategies are in great need to further diminish various hazardous air pollutants from iron and steel industry in the future. PMID:27054489

  20. On-road, in-use gaseous emission measurements by remote sensing of school buses equipped with diesel oxidation catalysts and diesel particulate filters.

    PubMed

    Burgard, Daniel A; Provinsal, Melissa N

    2009-12-01

    A remote sensing device was used to obtain on-road and in-use gaseous emission measurements from three fleets of schools buses at two locations in Washington State. This paper reports each fleet's carbon monoxide (CO), hydrocarbon (HC), nitric oxide (NO), and nitrogen dioxide (NO2) mean data. The fleets represent current emission retrofit technologies, such as diesel particulate filters and diesel oxidation catalysts, and a control fleet. This study shows that CO and HC emissions decrease with the use of either retrofit technology when compared with control buses of the same initial emission standards. The CO and HC emission reductions are consistent with published U.S. Environmental Protection Agency verified values. The total oxides of nitrogen (NOx), NO, and the NO2/NOx ratio all increase with each retrofit technology when compared with control buses. As was expected, the diesel particulate filters emitted significantly higher levels of NO2 than the control fleet because of the intentional conversion of NO to NO2 by these systems. Most prior research suggests that NOx emissions are unaffected by the retrofits; however, these previous studies have not included measurements from retrofit devices on-road and after nearly 5 yr of use. Two 2006 model-year buses were also measured. These vehicles did not have retrofit devices but were built to more stringent new engine standards. Reductions in HCs and NOx were observed for these 2006 vehicles in comparison to other non-retrofit earlier model-year vehicles. PMID:20066912

  1. Probe into Gaseous Pollution and Assessment of Air Quality Benefit under Sector Dependent Emission Control Strategies over Megacities in Yangtze River Delta, China

    SciTech Connect

    Dong, Xinyi; Gao, Yang; Fu, Joshua S.; Li, Juan; Huang, Kan; Zhuang, G.; Zhou, Ying

    2013-11-01

    On February 29th 2012, China published its new National Ambient Air Quality Standard (CH-NAAQS) aiming at revising the standards and measurements for both gaseous pollutants including ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2), and also particle pollutants including PM10 and PM2.5. In order to understand the air pollution status regarding this new standard, the integrated MM5/CMAQ modeling system was applied over Yangtze River Delta (YRD) within this study to examine the criteria gaseous pollutants listed in the new CH-NAAQS. Sensitivity simulations were also conducted to assess the responses of gaseous pollutants under 8 different sector-dependent emission reduction scenarios in order to evaluate the potential control strategies. 2006 was selected as the simulation year in order to review the air quality condition at the beginning of China’s 11th Five-Year-Plan (FYP, from 2006 to 2010), and also compared with air quality status in 2010 as the end of 11th FYP to probe into the effectiveness of the national emission control efforts. Base case simulation showed distinct seasonal variation for gaseous pollutants: SO2, and NO2 were found to have higher surface concentrations in winter while O3 was found to have higher concentrations in spring and summer than other seasons. According to the analyses focused on 3 megacities within YRD, Shanghai, Nanjing, and Hangzhou, we found different air quality conditions among the cities: NO2 was the primary pollutant that having the largest number of days exceeding the CH-NAAQS daily standard (80 μg/m3) in Shanghai (59 days) and Nanjing (27 days); SO2 was the primary pollutant with maximum number of days exceeding daily air quality standard (150 μg/m3) in Hangzhou (28 days), while O3 exceeding the daily maximum 8-hour standard (160 μg/m3) for relatively fewer days in all the three cities (9 days in Shanghai, 14 days in Nanjing, and 11 days in Hangzhou). Simulation results from predefined potential applicable

  2. Criticality and characteristic neutronic analysis of a transient-state shockwave in a pulsed spherical gaseous uranium-hexafluoride reactor

    NASA Astrophysics Data System (ADS)

    Boles, Jeremiah Thomas

    The purpose of this study is to analyze the theoretical criticality of a spherical uranium-hexafluoride reactor with a transient, pulsed shockwave emanating from the center of the sphere in an outward-radial direction. This novel nuclear reactor design, based upon pulsed fission in a spherical enclosure is proposed for possible use in direct energy conversion, where the energy from fission products is captured through the use of electrostatic fields or through induction. An analysis of the dynamic behavior of the shockwave in this reactor is the subject of this thesis. As a shockwave travels through a fluid medium, the characteristics of the medium will change across the shockwave boundary. Pressure, temperature, and density are all affected by the shockwave. Changes in these parameters will affect the neutronic characteristics of a fissile medium. If the system is initially in a subcritical state, the increases in pressure, temperature, and density, all brought about by the introduction of the shockwave, will increase the reactivity of the nuclear system, creating a brief super critical state that will return to a subcritical state after the shockwave dissipates. Two major problems are required to be solved for this system. One is the effects of the shockwave on the gas, and the second is the resulting effects on system criticality. These problems are coupled due to the unique nature of the speed of the expanding shockwave in the uranium-hexafluoride medium and the energy imparted to the system by the shockwave with respect to the fissile uranium-hexafluoride. Using compressible flow and shockwave theories, this study determines the properties of the gaseous medium for reference points before, during, and behind the shockwave as it passes through the fissile medium. These properties include pressure changes, temperature changes, and density changes that occur to the system. Using the parameters calculated from the shockwave, the neutron transport equation is

  3. Extracting Microwave Emissivity Characteristics over City using AMSR-E

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Zhang, L.; Jiang, L.; Li, Y.

    2010-12-01

    The spectrums of different land types are very important in the application of remote sensing. Different spectrums of different land types can be used in surface classification, change detection, and so on. The microwave emissivity over land is the foundation of land parameters retrieval using passive microwave remote sensing. It depends on land type due to different objects’ structure, moisture and roughness on the earth. It has shown that the land surface microwave emissivity contributed to atmosphere temperature and moisture retrieval. Meanwhile, it depends on land type, vegetation cover, and moisture et al.. There are many researches on microwave emissivity of various land types, such as bare soil, vegetation, snow, but city was less mentioned [1]. However, with the development of society, the process of urbanization accelerated quickly. The area of city expanded fast and the fraction of city area increased in one microwave pixel, especially in The North China Plain (about 30%). The passive microwave pixel containing city has impact on satellite observation and surface parameters retrieval then. So it is essential to study the emissivity of city in order to improve the accuracy of land surface parameters retrieval from passive microwave remote sensing. To study the microwave emissivity of city, some ‘pure’ city pixels were selected according to IGBP classification data, which was defined the fraction cover of city is larger than 85%. The city emissivity was calculated using AMSR-E L2A brightness temperature and GLDAS land surface temperature data at different frequencies and polarizations over 2008 in China. Then the seasonal variation was analyzed along the year. Finally, the characteristic of city emissivity were compared with some meteorological data, seeking the relationship between city emissivity and climatic factors. The results have shown that the emissivity of city was different for different frequencies. It increased with the frequency becoming

  4. Emission spectra of the cations of 1,3- and 1,4-dibromotetrafluorobenzene and of 1,3,5-tribromotrifluorobenzene in the gaseous phase

    USGS Publications Warehouse

    Maier, John Paul; Marthaler, O.; Mohraz, Manijeh; Shiley, R.H.

    1980-01-01

    A search was made for radiative decay of electronically excited cations of 24 bromobenzenes and of their fluoro-substituted derivatives in the gaseous phase. The only emission spectra detected were for the cations of 1,3- and 1,4-dibromotetrafluorobenzene and of 1,3,5-tribromotrifluorobenzene. The band systems, which are found between 670 and 830 nm, are assigned to the B(??-1) ??? A(??-1), X(??-1) electronic transitions of these cations. The assignments are based on the Ne(I) photoelectron spectra which are also presented for some of the studied species. The interpretation for the absence of detectable emission is that the nature of the B cationic states is ??-1, except in the case of 1,3- and 1,4-dibromobenzene cations for which B states are still formed by ??-1 processes. Possible reasons for these observations are discussed. The symmetries of the lowest three electronic states of the studied cations are given. ?? 1980.

  5. Thermal and emission characteristics of a CAN combustor

    NASA Astrophysics Data System (ADS)

    Shah, Rupesh D.; Banerjee, Jyotirmay

    2016-03-01

    Experimental investigations are carried out to establish the thermal and emission characteristics of a CAN combustor. Temperature and emission levels at the combustor exit are measured for different swirler vane angles and air fuel ratios (AFR). Swirler vane angle is varied from 15° to 60° in steps of 15°. AFR is varied in the range of 41-51. Experimental analysis is carried out using methane as fuel. Measured temperature variation at combustor outlet indicates that the hot product of combustor flows near the liner wall. Gradient of temperature near the wall decreases as the swirler vane angle (and corresponding swirl number) is increased. The peak temperature reduces at higher value of AFR. Emission level of carbon monoxide decreases with increase in AFR and swirler vane orientation. A higher level of NOX emission is observed for AFR of 45. This is due to change in shape and strength of the recirculation region in the primary zone of the combustor.

  6. 40 CFR Appendix Xvi to Part 86 - Pollutant Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... Where: Ywm = Weighted mass emissions of each pollutant, i.e., HC, CO, NOX or CO , in grams per vehicle mile. Yct = Mass emissions as calculated from the “transient” phase of the cold start test, in grams... grams per test phase. Ys = Mass emissions as calculated from the “stabilized” phase of the cold...

  7. 40 CFR Appendix Xvi to Part 86 - Pollutant Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Where: Ywm = Weighted mass emissions of each pollutant, i.e., HC, CO, NOX or CO , in grams per vehicle mile. Yct = Mass emissions as calculated from the “transient” phase of the cold start test, in grams... grams per test phase. Ys = Mass emissions as calculated from the “stabilized” phase of the cold...

  8. Gaseous emissions from a heavy-duty engine equipped with SCR aftertreatment system and fuelled with diesel and biodiesel: assessment of pollutant dispersion and health risk.

    PubMed

    Tadano, Yara S; Borillo, Guilherme C; Godoi, Ana Flávia L; Cichon, Amanda; Silva, Thiago O B; Valebona, Fábio B; Errera, Marcelo R; Penteado Neto, Renato A; Rempel, Dennis; Martin, Lucas; Yamamoto, Carlos I; Godoi, Ricardo H M

    2014-12-01

    The changes in the composition of fuels in combination with selective catalytic reduction (SCR) emission control systems bring new insights into the emission of gaseous and particulate pollutants. The major goal of our study was to quantify NOx, NO, NO2, NH3 and N2O emissions from a four-cylinder diesel engine operated with diesel and a blend of 20% soybean biodiesel. Exhaust fume samples were collected from bench dynamometer tests using a heavy-duty diesel engine equipped with SCR. The target gases were quantified by means of Fourier transform infrared spectrometry (FTIR). The use of biodiesel blend presented lower concentrations in the exhaust fumes than using ultra-low sulfur diesel. NOx and NO concentrations were 68% to 93% lower in all experiments using SCR, when compared to no exhaust aftertreatment. All fuels increased NH3 and N2O emission due to SCR, a precursor secondary aerosol, and major greenhouse gas, respectively. An AERMOD dispersion model analysis was performed on each compound results for the City of Curitiba, assumed to have a bus fleet equipped with diesel engines and SCR system, in winter and summer seasons. The health risks of the target gases were assessed using the Risk Assessment Information System For 1-h exposure of NH3, considering the use of low sulfur diesel in buses equipped with SCR, the results indicated low risk to develop a chronic non-cancer disease. The NOx and NO emissions were the lowest when SCR was used; however, it yielded the highest NH3 concentration. The current results have paramount importance, mainly for countries that have not yet adopted the Euro V emission standards like China, India, Australia, or Russia, as well as those already adopting it. These findings are equally important for government agencies to alert the need of improvements in aftertreatment technologies to reduce pollutants emissions. PMID:25217745

  9. Benefits of China's efforts in gaseous pollutant control indicated by the bottom-up emissions and satellite observations 2000-2014

    NASA Astrophysics Data System (ADS)

    Xia, Yinmin; Zhao, Yu; Nielsen, Chris P.

    2016-07-01

    To evaluate the effectiveness of national air pollution control policies, the emissions of SO2, NOX, CO and CO2 in China are estimated using bottom-up methods for the most recent 15-year period (2000-2014). Vertical column densities (VCDs) from satellite observations are used to test the temporal and spatial patterns of emissions and to explore the ambient levels of gaseous pollutants across the country. The inter-annual trends in emissions and VCDs match well except for SO2. Such comparison is improved with an optimistic assumption in emission estimation that the emission standards for given industrial sources issued after 2010 have been fully enforced. Underestimation of emission abatement and enhanced atmospheric oxidization likely contribute to the discrepancy between SO2 emissions and VCDs. As suggested by VCDs and emissions estimated under the assumption of full implementation of emission standards, the control of SO2 in the 12th Five-Year Plan period (12th FYP, 2011-2015) is estimated to be more effective than that in the 11th FYP period (2006-2010), attributed to improved use of flue gas desulfurization in the power sector and implementation of new emission standards in key industrial sources. The opposite was true for CO, as energy efficiency improved more significantly from 2005 to 2010 due to closures of small industrial plants. Iron & steel production is estimated to have had particularly strong influence on temporal and spatial patterns of CO. In contrast to fast growth before 2011 driven by increased coal consumption and limited controls, NOX emissions decreased from 2011 to 2014 due to the penetration of selective catalytic/non-catalytic reduction systems in the power sector. This led to reduced NO2 VCDs, particularly in relatively highly polluted areas such as the eastern China and Pearl River Delta regions. In developed areas, transportation is playing an increasingly important role in air pollution, as suggested by the increased ratio of NO2 to SO

  10. Pyrolysis of rice straw with ammonium dihydrogen phosphate: Properties and gaseous potassium release characteristics during combustion of the products.

    PubMed

    Li, Hui; Han, Kuihua; Wang, Qian; Lu, Chunmei

    2015-12-01

    The effect of ammonium dihydrogen phosphate (NH4H2PO4) on rice straw (RS) carbonization was evaluated at temperatures of 350-650°C. The carbonized products of RS with NH4H2PO4 show higher solid and energy yields, but lower higher heating values than the carbonized RS at every carbonization temperature. The optimum carbonization operation of RS with NH4H2PO4 which has a higher energy yield at a lower solid volume may be determined between 350 and 450°C, and RS with NH4H2PO4 carbonized at 450°C presents better pore properties than carbonized RS. The carbonized products of RS with NH4H2PO4 all have lower gaseous potassium release ratios than those of RS carbonized at the same temperature at combustion temperatures of 700-1000°C by retaining potassium in non-volatile phosphorus compounds with high melting points. It is an effective method for inhibiting the gaseous potassium release during combustion of the carbonized products. PMID:26340027

  11. Heavy duty liquid and gaseous fuel emissions database test results from four alternative fuel configurations of the Caterpillar 3406 engine

    SciTech Connect

    Waldman, D.J. )

    1990-06-01

    Through the cooperation of several organizations including the Oak Ridge National Laboratory (ORNL) acting under the auspices of the Doe Alternative Fuels Utilization Program, heavy duty transient and steady-state emissions tests were conducted on four alternative fuel configurations of the Caterpillar 3406 engine. These included a diesel baseline, glow plug ignited methanol (diesel cycle), lean-burn spark ignited natural gas, and dual fuel (diesel pilot ignited natural gas). Results indicated methanol and natural gas both show excellent potential for low NOx and low particulate emissions. With these fuels however, unburned fuel emissions were much higher, especially in the dual fuel case, than the diesel baseline. Particulate emissions from the methanol and lean burn gas engines are thought to be almost entirely lube oil sourced. All of the configurations will require significant reduction in hydrocarbon and/or particulate emissions in order to meet the 1994 EPA emissions standards for heavy duty truck engines. 3 refs., 23 figs., 15 tabs.

  12. Pore geometry of dispenser cathode surface vs. emission characteristics, and Ba recovery characteristics after ion bombardment

    NASA Astrophysics Data System (ADS)

    Higuchi, Toshiharu; Nakamura, Osamu; Matsumoto, Sadao; Uda, Eiichirou

    1999-05-01

    A study was conducted to investigate the emission characteristics and barium recovery characteristics after ion bombardment of two types of Ir-coated dispenser cathodes having a pore density on the surface layer of the cathodes of 4×10 4 and 1.3×10 4 pores/mm 2. Cathode current was measured under pulse operation in a range of 0.1-9% duty cycle. When the duty cycle dependence of emissions was examined, the current densities of both cathodes were the same in the case of 0.1% duty cycle, delivering about 12 A/cm 2. The work functions also showed the same value. However, evaluations of 4% duty cycle and 9% duty cycle found that the cathode with a higher pore density showed emission characteristics higher by 50% and 70%. Regarding the recovery time of barium and oxygen after argon ion bombardment with Auger electron spectroscopy (AES), the low-pore-density cathode required as long as 3 min for recovery, whereas the high-pore-density cathode recovered in 1.1 min. From the above experiments, it was clarified that emission characteristics under high duty and barium recovery characteristics after ion bombardment can be improved by increasing the pore density of the surface layer. The basic mechanisms leading to these results were also theoretically considered by solving surface diffusion equations.

  13. Effect of N-(n-butyl) thiophosphoric triamide and 3,4 dimethylpyrazole phosphate on gaseous emissions from grasslands under different soil water contents.

    PubMed

    Menéndez, S; Merino, P; Pinto, M; González-Murua, C; Estavillo, J M

    2009-01-01

    The intensification of grassland systems is leading to serious environmental risks due to the large input of nitrogen (N) in fertilizers and the subsequent gaseous losses. Addition of nitrification inhibitors (NI) or urease activity inhibitors to fertilizers could reduce these losses to the atmosphere. In the present study, the effects of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) and the urease activity inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) were evaluated on NH3, N2O, NO, and CO2 emissions. Ammonium sulphate nitrate (ASN), urea and cattle slurry were applied at a rate of 70 kg N ha(-1) to a mixed clover-ryegrass sward in the Basque Country (northern Spain) under different soil water contents. NH3 and NO emissions were determined by photoacoustic and chemiluminescence respectively using an open chamber technique while N2O and CO2 emissions were measured by photoacoustic using a closed chamber technique. When the water filled pore space (WFPS) was under 60%, the application of NBPT reduced NO emissions a 34% on urea and an 18% on slurry, and the application of DMPP reduced them a 2% on ASN and a 4% on slurry. No significant effect was observed on NH3 losses. When WFPS was over 60%, no effect could be observed on NO and N2O emissions after the application of both inhibitors, but NH3 losses were reduced a 31% by NBPT when applied with the slurry. Carbon dioxide emissions were unaffected by the use of DMPP or NBPT at any soil water content. Neither grassland yield nor herbage N concentration were influenced by the application of both inhibitors. PMID:19141792

  14. Monitoring of harmful gaseous emissions from land transport vehicles using a mid-infrared optical fibre sensor

    NASA Astrophysics Data System (ADS)

    Mulrooney, Jim; Clifford, John; Fitzpatrick, Colin; Lewis, Elfed

    2006-04-01

    This paper discusses the development of an optical fibre sensor suitable for the detection of gas emissions from motor vehicles based on mid-infrared spectroscopy. Initial measurements are presented for carbon dioxide emissions from a petrol engine using low-cost mid-infrared components, and a practical detection system, which could be fitted to a vehicle, is outlined.

  15. A description of the correlated k distributed method for modeling nongray gaseous absorption, thermal emission, and multiple scattering in vertically inhomogeneous atmospheres

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew A.; Oinas, Valdar

    1991-01-01

    A radiative transfer method for treating nongray gaseous absorption and thermal emission in vertically inhomogeneous multiple scattering atmospheres is described. Probability density distributions of absorption coefficient strength are derived from line-by-line calculations to construct line-by-line and band model based k distributions. The monotonic ordering of absorption coefficient strengths in these k distributions implicitly preserves the monochromatic structure of the atmosphere at different pressure levels, thus simulating monochromatic spectral integration at a fraction of the line-by-line computing cost. The k distribution approach also permits accurate modeling of overlapping absorption by different atmospheric gases and accurate treatment of nongray absorption in multiple scattering media. It is shown that the correlated k distribution method is capable of achieving numerical accuracy to within 1 percent of cooling rates obtained with line-by-line calculations throughout the troposphere and most of the stratosphere.

  16. Particle and gaseous emissions from compressed natural gas and ultralow sulphur diesel-fuelled buses at four steady engine loads.

    PubMed

    Jayaratne, E R; Ristovski, Z D; Meyer, N; Morawska, L

    2009-04-01

    Exhaust emissions from thirteen compressed natural gas (CNG) and nine ultralow sulphur diesel in-service transport buses were monitored on a chassis dynamometer. Measurements were carried out at idle and at three steady engine loads of 25%, 50% and 100% of maximum power at a fixed speed of 60 km h(-1). Emission factors were estimated for particle mass and number, carbon dioxide and oxides of nitrogen for two types of CNG buses (Scania and MAN, compatible with Euro 2 and 3 emission standards, respectively) and two types of diesel buses (Volvo Pre-Euro/Euro1 and Mercedez OC500 Euro3). All emission factors increased with load. The median particle mass emission factor for the CNG buses was less than 1% of that from the diesel buses at all loads. However, the particle number emission factors did not show a statistically significant difference between buses operating on the two types of fuel. In this paper, for the very first time, particle number emission factors are presented at four steady state engine loads for CNG buses. Median values ranged from the order of 10(12) particles min(-)(1) at idle to 10(15) particles km(-)(1) at full power. Most of the particles observed in the CNG emissions were in the nanoparticle size range and likely to be composed of volatile organic compounds The CO2 emission factors were about 20% to 30% greater for the diesel buses over the CNG buses, while the oxides of nitrogen emission factors did not show any difference due to the large variation between buses. PMID:19185331

  17. Effectiveness of selective catalytic reduction systems on reducing gaseous emissions from an engine using diesel and biodiesel blends.

    PubMed

    Borillo, Guilherme C; Tadano, Yara S; Godoi, Ana F L; Santana, Simone S M; Weronka, Fernando M; Penteado Neto, Renato A; Rempel, Dennis; Yamamoto, Carlos I; Potgieter-Vermaak, Sanja; Potgieter, Johannes H; Godoi, Ricardo H M

    2015-03-01

    The aim of this investigation was to quantify organic and inorganic gas emissions from a four-cylinder diesel engine equipped with a urea selective catalytic reduction (SCR) system. Using a bench dynamometer, the emissions from the following mixtures were evaluated using a Fourier transform infrared (FTIR) spectrometer: low-sulfur diesel (LSD), ultralow-sulfur diesel (ULSD), and a blend of 20% soybean biodiesel and 80% ULSD (B20). For all studied fuels, the use of the SCR system yielded statistically significant (p < 0.05) lower NOx emissions. In the case of the LSD and ULSD fuels, the SCR system also significantly reduced emissions of compounds with high photochemical ozone creation potential, such as formaldehyde. However, for all tested fuels, the SCR system produced significantly (p < 0.05) higher emissions of N2O. In the case of LSD, the NH3 emissions were elevated, and in the case of ULSD and B20 fuels, the non-methane hydrocarbon (NMHC) and total hydrocarbon of diesel (HCD) emissions were significantly higher. PMID:25634131

  18. Field measurements of small marine craft gaseous emission factors during NEAQS 2004 and TexAQS 2006.

    PubMed

    Lerner, Brian M; Murphy, Paul C; Williams, Eric J

    2009-11-01

    Exhaust emission factors were calculated for a number (n = 116) of small marine craft encountered during the 2004 New England Air Quality Study-International Transport and Chemical Transformation and 2006 Texas Air Quality Study II field campaigns. Emission factors are reported for NO(x), SO(2), and CO in units of grams of pollutant per kilogram of fuel. These factors are compared to emission factors derived from the U.S. Environmental Protection Agency (EPA) NONROAD model, separated into spark-ignition and compression-ignition sources. NO(x) emission factors observed were significantly and substantially higher than predicted by the model by a factor of 2-10. CO emission factors were not significantly different than the model outputs. Because of the correlation between exhaust hydrocarbon and CO for marine craft, it is expected that EPA estimates of hydrocarbon exhaust emission factors are not significantly in error. Small commercial marine craft (e.g., inshore fishing trawlers) are not part of NONROAD, but their measured emission factors were comparable to those of large diesel recreational marine craft in the model. PMID:19924946

  19. Inter-Annual Variability of Area-Scaled Gaseous Carbon Emissions from Wetland Soils in the Liaohe Delta, China

    PubMed Central

    Ye, Siyuan; Krauss, Ken W.; Brix, Hans; Wei, Mengjie; Olsson, Linda; Yu, Xueyang; Ma, Xueying; Wang, Jin; Yuan, Hongming; Zhao, Guangming; Ding, Xigui; Moss, Rebecca F.

    2016-01-01

    Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity <18 PSU. CH4 emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling. PMID:27501148

  20. Inter-Annual Variability of Area-Scaled Gaseous Carbon Emissions from Wetland Soils in the Liaohe Delta, China.

    PubMed

    Ye, Siyuan; Krauss, Ken W; Brix, Hans; Wei, Mengjie; Olsson, Linda; Yu, Xueyang; Ma, Xueying; Wang, Jin; Yuan, Hongming; Zhao, Guangming; Ding, Xigui; Moss, Rebecca F

    2016-01-01

    Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity <18 PSU. CH4 emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling. PMID:27501148

  1. A fully integrated isoprenoid emissions model coupling emissions to photosynthetic characteristics.

    PubMed

    Grote, Rüdiger; Morfopoulos, Catherine; Niinemets, Ülo; Sun, Zhihong; Keenan, Trevor F; Pacifico, Federica; Butler, Tim

    2014-08-01

    The lack of a mechanistic basis has hampered modelling isoprene emission responses to environmental drivers, in particular the simulation of isoprene emissions under different CO₂ concentrations. Here, we advance previous semi-mechanistic model formulations by introducing a model that explicitly links electron availability for other purpose than carbon assimilation (or available energy for secondary metabolism processes; supply-constraint) and enzyme activity (capacity-constraint) to emissions. We furthermore investigate the sensitivity of the model to variations in photosynthetic and emission-specific parameters. By comparing species-specific simulations with experimental data, we demonstrate that differences in photosynthetic characteristics can explain inter-species differences in emissions. Interestingly, the seasonal development of emissions could also be explained to some degree by the change in energy supply from photosynthesis throughout the season. In addition, we show that the principal responses are not limited to isoprene but can be formulated to describe the emission of other light-dependent volatile species. The proposed model is suitable for implementation into regional and global models, particularly those that already provide species-specific photosynthesis estimates. PMID:24661098

  2. Power generation and gaseous emissions performance of an internal combustion engine fed with blends of soybean and beef tallow biodiesel.

    PubMed

    Schirmer, Waldir Nagel; Gauer, Mayara Ananda; Tomaz, Edson; Rodrigues, Paulo Rogério Pinto; de Souza, Samuel Nelson Melegari; Chaves, Luiz Inácio; Villetti, Lucas; Olanyk, Luciano Zart; Cabral, Alexandre Rodrigues

    2016-01-01

    This study aimed to compare the performance of an internal combustion engine fed with blends of biodiesel produced from soybean and diesel, and blends of biodiesel produced from beef tallow and diesel. Performance was evaluated in terms of power generated at low loading conditions (0.5, 1.0 and 1.5 kW) and emission of organic and inorganic pollutants. In order to analyse inorganic gases (CO, SO2 and NOx), an automatic analyser was used and the organic emissions (benzene, toluene, ethylbenzene and xylene - BTEX) were carried out using a gas chromatograph. The results indicate that the introduction of the two biodiesels in the fuel caused a reduction in CO, SO2 and BTEX emissions. In addition, the reduction was proportional to the increase in loading regime. Beef tallow biodiesels presented better results regarding emission than soybean biodiesels. The use of pure biodiesels also presented a net reduction in pollutant gas emissions without hindering the engine generator performance. PMID:26581845

  3. A fully integrated isoprenoid emissions model coupling emissions to photosynthetic characteristics

    PubMed Central

    Grote, Rüdiger; Morfopoulos, Catherine; Niinemets, Ülo; Sun, Zhihong; Keenan, Trevor; Pacifico, Federica; Butler, Tim

    2015-01-01

    Recently, a biogenic isoprene emission model with improved CO2 dependency was developed for global change applications (Morfopoulos et al., 2013). The model is based on the mechanistic linkage between isoprene emission and the availability of reducing power. Here, we advance the model formulation by introducing an explicit link between the electron transport (supply-constraint) and enzyme activity (capacity-constraint). We furthermore investigate the sensitivity of the model to variations in photosynthetic and emission-specific parameters. By comparing species-specific simulations with experimental data, we demonstrate that differences in photosynthetic characteristics can well explain inter-species differences in emissions. Interestingly, also the seasonal development emissions could be explained to some degree by the change of energy supply from photosynthesis throughout the season. In addition, we show that the principal responses are not limited to isoprene but can be formulated to describe the emission of all light-dependent volatile species. Thus, the model is a good candidate to be implemented in regional and global models that already provide species-specific photosynthesis estimates. PMID:24661098

  4. Odor, gaseous and PM10 emissions from small scale combustion of wood types indigenous to Central Europe

    NASA Astrophysics Data System (ADS)

    Kistler, Magdalena; Schmidl, Christoph; Padouvas, Emmanuel; Giebl, Heinrich; Lohninger, Johann; Ellinger, Reinhard; Bauer, Heidi; Puxbaum, Hans

    2012-05-01

    In this study, we investigated the emissions, including odor, from log wood stoves, burning wood types indigenous to mid-European countries such as Austria, Czech Republic, Hungary, Slovak Republic, Slovenia, Switzerland, as well as Baden-Württemberg and Bavaria (Germany) and South Tyrol (Italy). The investigations were performed with a modern, certified, 8 kW, manually fired log wood stove, and the results were compared to emissions from a modern 9 kW pellet stove. The examined wood types were deciduous species: black locust, black poplar, European hornbeam, European beech, pedunculate oak (also known as “common oak”), sessile oak, turkey oak and conifers: Austrian black pine, European larch, Norway spruce, Scots pine, silver fir, as well as hardwood briquettes. In addition, “garden biomass” such as pine cones, pine needles and dry leaves were burnt in the log wood stove. The pellet stove was fired with softwood pellets. The composite average emission rates for log wood and briquettes were 2030 mg MJ-1 for CO; 89 mg MJ-1 for NOx, 311 mg MJ-1 for CxHy, 67 mg MJ-1 for particulate matter PM10 and average odor concentration was at 2430 OU m-3. CO, CxHy and PM10 emissions from pellets combustion were lower by factors of 10, 13 and 3, while considering NOx - comparable to the log wood emissions. Odor from pellets combustion was not detectable. CxHy and PM10 emissions from garden biomass (needles and leaves) burning were 10 times higher than for log wood, while CO and NOx rise only slightly. Odor levels ranged from not detectable (pellets) to around 19,000 OU m-3 (dry leaves). The odor concentration correlated with CO, CxHy and PM10. For log wood combustion average odor ranged from 536 OU m-3 for hornbeam to 5217 OU m-3 for fir, indicating a considerable influence of the wood type on odor concentration.

  5. Summary of performance data for technologies to control gaseous, odor, and particulate emissions from livestock operations: Air management practices assessment tool (AMPAT).

    PubMed

    Maurer, Devin L; Koziel, Jacek A; Harmon, Jay D; Hoff, Steven J; Rieck-Hinz, Angela M; Andersen, Daniel S

    2016-06-01

    The livestock and poultry production industry, regulatory agencies, and researchers lack a current, science-based guide and data base for evaluation of air quality mitigation technologies. Data collected from science-based review of mitigation technologies using practical, stakeholders-oriented evaluation criteria to identify knowledge gaps/needs and focuses for future research efforts on technologies and areas with the greatest impact potential is presented in the Literature Database tab on the air management practices tool (AMPAT). The AMPAT is web-based (available at www.agronext.iastate.edu/ampat) and provides an objective overview of mitigation practices best suited to address odor, gaseous, and particulate matter (PM) emissions at livestock operations. The data was compiled into Excel spreadsheets from a literature review of 265 papers was performed to (1) evaluate mitigation technologies performance for emissions of odor, volatile organic compounds (VOCs), ammonia (NH3), hydrogen sulfide (H2S), particulate matter (PM), and greenhouse gases (GHGs) and to (2) inform future research needs. PMID:27158660

  6. Summary of performance data for technologies to control gaseous, odor, and particulate emissions from livestock operations: Air management practices assessment tool (AMPAT)

    PubMed Central

    Maurer, Devin L.; Koziel, Jacek A.; Harmon, Jay D.; Hoff, Steven J.; Rieck-Hinz, Angela M.; Andersen, Daniel S.

    2016-01-01

    The livestock and poultry production industry, regulatory agencies, and researchers lack a current, science-based guide and data base for evaluation of air quality mitigation technologies. Data collected from science-based review of mitigation technologies using practical, stakeholders-oriented evaluation criteria to identify knowledge gaps/needs and focuses for future research efforts on technologies and areas with the greatest impact potential is presented in the Literature Database tab on the air management practices tool (AMPAT). The AMPAT is web-based (available at www.agronext.iastate.edu/ampat) and provides an objective overview of mitigation practices best suited to address odor, gaseous, and particulate matter (PM) emissions at livestock operations. The data was compiled into Excel spreadsheets from a literature review of 265 papers was performed to (1) evaluate mitigation technologies performance for emissions of odor, volatile organic compounds (VOCs), ammonia (NH3), hydrogen sulfide (H2S), particulate matter (PM), and greenhouse gases (GHGs) and to (2) inform future research needs. PMID:27158660

  7. A NONSTEADY-STATE ANALYTICAL MODEL TO PREDICT GASEOUS EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM LANDFILLS. (R825689C072)

    EPA Science Inventory

    Abstract

    A general mathematical model is developed to predict emissions of volatile organic compounds (VOCs) from hazardous or sanitary landfills. The model is analytical in nature and includes important mechanisms occurring in unsaturated subsurface landfill environme...

  8. Long-term records of fire occurrence and their implications for gaseous and particulate emissions to the atmosphere

    SciTech Connect

    Clark, J.S.; Stocks, B.J. Forestry Canada, Sault Ste, Marie, Ontario )

    1993-06-01

    Changing climate and land use appear to importantly affect the biosphere by way of impacts on fire regimes. Feedback effects on climate and air quality are likely through emissions of trace gases, aerosols, and particulates that affect radiation budgets, stability of the troposphere, and biogeochemical and hydrologic cycles. Paleorecords of biomass burning are available in the form of stratigraphic charcoal in lake and mire deposits and fire scars on trees. When taken together with recent emissions data from experimental bums and wildland fires they hold promise for estimation of how changing fire regimes may be affecting atmospheric composition. We synthesize existing evidence for effects of global change on fire regimes for each of the major biomes. Fire regimes vary in their sensitivities to changing climate, with woodland/savanna types and boreal forest among the most sensitive. Emissions have greatly increased with changing human influences in some vegetation types (temperate and some low-latitude biomes) and decreased in others (temperate pine forests). Some biomes, including boreal forests, hold promise for rather detailed reconstructions of past emissions. We recommend that future efforts focus on those regions where the importance of fire and availability of paleodata are greatest.

  9. Flow and Emissions Characteristics of Multi-Swirler Combustor

    NASA Astrophysics Data System (ADS)

    Gutmark, Ephraim; Li, Guoqiang

    2003-11-01

    Modern industrial gas-turbine spray combustors feature multiple swirlers and distributed fuel injection for rapid mixing and stabilization. The flow field of this combustor, the related combustion characteristics and their control are discussed. The velocity flow field downstream of a Triple Annular Research Swirler (TARS) was characterized. Multiple combinations of swirlers were tested in cold flow under atmospheric conditions with and without confining combustion chamber. The experiments showed that a central recirculation zone (CTRZ), an annular jet with internal and external shear layers dominated the flow field downstream of TARS. Compared to unconfined case, flow with confined tube showed an enlarged CTRZ region and a recirculation region in the expansion corner with reduced concentration of turbulence intensity in the jet region. TARS also produced low emissions of NOx and CO. Measurements were performed to study the effects of several factors, including swirler combinations, exhaust nozzle size, air assist for fuel atomization and mixing length on NOx and CO emissions and combustion instability. The data showed that emissions and stability depend on the combination of several of these factors.

  10. Mode characteristics and directional emission for square microcavity lasers

    NASA Astrophysics Data System (ADS)

    Yang, Yue-De; Huang, Yong-Zhen

    2016-06-01

    Square microcavities with high quality factor whispering-gallery-like modes have a series of novel optical properties and can be employed as compact-size laser resonators. In this paper, the mode characteristics of square optical microcavities and the lasing properties of directional-emission square semiconductor microlasers are reviewed for the realization of potential light sources in the photonic integrated circuits and optical interconnects. A quasi-analytical model is introduced to describe the confined modes in square microcavities, and high quality factor whispering-gallery-like modes are predicted by the mode-coupling theory and confirmed by the numerical simulation. An output waveguide directly coupled to the position with weak mode field is used to achieve directional emission and control the lasing mode. Electrically-pumped InP-based directional-emission square microlasers are realized at room temperature, and the lasing spectra agree well with the mode analysis. Different kinds of square microcavity lasers, including dual-mode laser with a tunable interval, single-mode laser with a wide tunable wavelength range, and high-speed direct-modulated laser are also demonstrated experimentally.

  11. Source characteristics of Jovian narrow-band kilometric radio emissions

    NASA Astrophysics Data System (ADS)

    Reiner, M. J.; Fainberg, J.; Stone, R. G.; Kaiser, M. L.; Desch, M. D.; Manning, R.; Zarka, P.; Pedersen, B.-M.

    1993-07-01

    New observations of Jovian narrow-band kilometric (nKOM) radio emissions were made by the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in early February 1992. These observations have demonstrated the unique capability of the URAP instrument for determining both the direction and polarization of nKOM radio sources. An important result is the discovery that nKOM radio emission originates from a number of distinct sources located at different Jovian longitudes and at the inner and outermost regions of the Io plasma torus. These sources have been tracked for several Jovian rotations, yielding their corotational lags, their spatial and temporal evolution, and their radiation characteristics at both low latitudes far from Jupiter and at high latitudes near the planet. Both right-hand and left-hand circularly polarized nKOM sources were observed. The polarizations observed for sources in the outermost regions of the torus seem to favor extraordinary mode emission.

  12. Odor, gaseous and PM10 emissions from small scale combustion of wood types indigenous to Central Europe.

    PubMed

    Kistler, Magdalena; Schmidl, Christoph; Padouvas, Emmanuel; Giebl, Heinrich; Lohninger, Johann; Ellinger, Reinhard; Bauer, Heidi; Puxbaum, Hans

    2012-05-01

    In this study, we investigated the emissions, including odor, from log wood stoves, burning wood types indigenous to mid-European countries such as Austria, Czech Republic, Hungary, Slovak Republic, Slovenia, Switzerland, as well as Baden-Württemberg and Bavaria (Germany) and South Tyrol (Italy). The investigations were performed with a modern, certified, 8 kW, manually fired log wood stove, and the results were compared to emissions from a modern 9 kW pellet stove. The examined wood types were deciduous species: black locust, black poplar, European hornbeam, European beech, pedunculate oak (also known as "common oak"), sessile oak, turkey oak and conifers: Austrian black pine, European larch, Norway spruce, Scots pine, silver fir, as well as hardwood briquettes. In addition, "garden biomass" such as pine cones, pine needles and dry leaves were burnt in the log wood stove. The pellet stove was fired with softwood pellets. The composite average emission rates for log wood and briquettes were 2030 mg MJ(-1) for CO; 89 mg MJ(-1) for NOx, 311 mg MJ(-1) for CxHy, 67 mg MJ(-1) for particulate matter PM10 and average odor concentration was at 2430 OU m(-3). CO, CxHy and PM10 emissions from pellets combustion were lower by factors of 10, 13 and 3, while considering NOx - comparable to the log wood emissions. Odor from pellets combustion was not detectable. CxHy and PM10 emissions from garden biomass (needles and leaves) burning were 10 times higher than for log wood, while CO and NOx rise only slightly. Odor levels ranged from not detectable (pellets) to around 19,000 OU m(-3) (dry leaves). The odor concentration correlated with CO, CxHy and PM10. For log wood combustion average odor ranged from 536 OU m(-3) for hornbeam to 5217 OU m(-3) for fir, indicating a considerable influence of the wood type on odor concentration. PMID:23471123

  13. Odor, gaseous and PM10 emissions from small scale combustion of wood types indigenous to Central Europe

    PubMed Central

    Kistler, Magdalena; Schmidl, Christoph; Padouvas, Emmanuel; Giebl, Heinrich; Lohninger, Johann; Ellinger, Reinhard; Bauer, Heidi; Puxbaum, Hans

    2012-01-01

    In this study, we investigated the emissions, including odor, from log wood stoves, burning wood types indigenous to mid-European countries such as Austria, Czech Republic, Hungary, Slovak Republic, Slovenia, Switzerland, as well as Baden-Württemberg and Bavaria (Germany) and South Tyrol (Italy). The investigations were performed with a modern, certified, 8 kW, manually fired log wood stove, and the results were compared to emissions from a modern 9 kW pellet stove. The examined wood types were deciduous species: black locust, black poplar, European hornbeam, European beech, pedunculate oak (also known as “common oak”), sessile oak, turkey oak and conifers: Austrian black pine, European larch, Norway spruce, Scots pine, silver fir, as well as hardwood briquettes. In addition, “garden biomass” such as pine cones, pine needles and dry leaves were burnt in the log wood stove. The pellet stove was fired with softwood pellets. The composite average emission rates for log wood and briquettes were 2030 mg MJ−1 for CO; 89 mg MJ−1 for NOx, 311 mg MJ−1 for CxHy, 67 mg MJ−1 for particulate matter PM10 and average odor concentration was at 2430 OU m−3. CO, CxHy and PM10 emissions from pellets combustion were lower by factors of 10, 13 and 3, while considering NOx – comparable to the log wood emissions. Odor from pellets combustion was not detectable. CxHy and PM10 emissions from garden biomass (needles and leaves) burning were 10 times higher than for log wood, while CO and NOx rise only slightly. Odor levels ranged from not detectable (pellets) to around 19,000 OU m−3 (dry leaves). The odor concentration correlated with CO, CxHy and PM10. For log wood combustion average odor ranged from 536 OU m−3 for hornbeam to 5217 OU m−3 for fir, indicating a considerable influence of the wood type on odor concentration. PMID:23471123

  14. Adsorption characteristics of trichloroethylene and 1,1,1-trichloroethane onto activated carbon fiber in gaseous phase

    SciTech Connect

    Tanada, Seiki; Nakamura, Takeo; Xiaohong, Ma; Higuchi, Toshikazu; Shinoda, Sanji

    1992-07-01

    Trichloroethylene (TCE) and 1,1,1-trichloroethane (methylchloroform:MC) are major volatile chlorinated hydrocarbons, and the production amounts of these compounds run up to about 80,000-100,000 tons a year in Japan. TCE and MC were observed in groundwater in Japan as well as in the United States, so that the environmental contamination by these compounds became a serious problem. TCE and MC cause vertigo, headache, drunkenness and fatigue depending on central nervous system depress, and also liver or kidney lesion by inhalation as general toxicities. For prevention of the poisoning to workers, the permissible concentrations of TCE and MC vapors in work area have been set at 50ppm and 200ppm, respectively by Japan Association of Industrial Health. In the United States, those values are set at 100ppm and 350ppm by American Conference of Governmental Industrial Hygienists, respectively. In addition, TCE is considered to be carcinogenic because it causes liver cancer in mice. Furthermore, MC is considered to destroy the Ozone Layer. Though it is presumed that 40-70% of used TCE and MC in factories is exhausted to the atmosphere, there is no regulation now concerning the exhaustion of TCE and MC to the atmosphere. So that regards should be paid to the intake of TCE and MC from the atmosphere as well as from drinking water. In this paper, we studied the adsorption removal of TCE and MC by activated carbon fibers (ACFs) in gaseous phase pointing to the prevention against TCE and MC diffusion to the atmosphere and inhalation to workers. 9 refs., 3 figs., 2 tabs.

  15. An experimental study of gaseous exhaust emissions of diesel engine using blend of natural fatty acid methyl ester

    NASA Astrophysics Data System (ADS)

    Sudrajad, Agung; Ali, Ismail; Samo, Khalid; Faturachman, Danny

    2012-09-01

    Vegetable oil form in Natural Fatty Acid Methyl Ester (FAME) has their own advantages: first of all they are available everywhere in the world. Secondly, they are renewable as the vegetables which produce oil seeds can be planted year after year. Thirdly, they are friendly with our environment, as they seldom contain sulphur element in them. This makes vegetable fuel studies become current among the various popular investigations. This study is attempt to optimization of using blend FAME on diesel engine by experimental laboratory. The investigation experimental project is comparison between using blend FAME and base diesel fuel. The engine experiment is conducted with YANMAR TF120M single cylinder four stroke diesel engine set-up at variable engine speed with constant load. The data have been taken at each point of engine speed during the stabilized engine-operating regime. Measurement of emissions parameters at difference engine speed conditions have generally indicated lower in emission NOx, but slightly higher on CO2 emission. The result also shown that the blends FAME are good in fuel consumption and potentially good substitute fuels for diesel engine

  16. Trends in concentrations of atmospheric gaseous and particulate species in rural eastern Tennessee as related to primary emission reductions

    NASA Astrophysics Data System (ADS)

    Tanner, R. L.; Bairai, S. T.; Mueller, S. F.

    2015-09-01

    Air quality measurements at Look Rock, Tennessee - on the western edge of the Great Smoky Mountains National Park - were begun in 1980 and expanded during the 1980s to a National Park Service (NPS) IMPROVE network station. Measurements were expanded again by the Tennessee Valley Authority (TVA, 1999-2007) to examine the effects of electric generating unit (EGU) emission reductions of SO2 and NOx on air quality at the station. Analysis of temporal trends (1999-2013) has been conducted at the site in collaboration with activities related to the 2013 Southeast Atmosphere Study (SAS) at Look Rock and other southeastern US locations. Key findings from these trend studies include the observation that primary pollutant levels have consistently tracked emission reductions from EGUs and other primary sources in the region, but reductions in secondary pollutants such as particulate sulfate and, specifically, ozone have been smaller compared to reductions in primary emissions. Organic carbonaceous material (OM) remains a major contributor (30-40 % in the period 2009-2013) to fine particulate mass at the site, as confirmed by ACSM measurements at the site in 2013. A large portion (65-85 %) of carbon in OM derives from modern carbon sources based on 14C measurements. Important parameters affecting ozone levels, fine mass, and visibility also include the specific diurnal meteorology at this ridge-top site, its location in a predominantly mixed-deciduous forest, and the presence of primary sources of precursors at distances of 50-500 km from the site in all directions.

  17. Trends in concentrations of atmospheric gaseous and particulate species in rural eastern Tennessee as related to primary emissions reductions

    NASA Astrophysics Data System (ADS)

    Tanner, R. L.; Bairai, S. T.; Mueller, S. F.

    2015-05-01

    Air quality measurements at Look Rock, Tennessee - on the western edge of the Great Smoky Mountains National Park - were begun in 1980 and expanded during the 1980s to a National Park Service (NPS) IMPROVE network station. Measurements were expanded again by the Tennessee Valley Authority (TVA, 1999-2007) to examine the effects of electric generating unit (EGU) emission reductions of SO2 and NOx on air quality at the station. Analysis of temporal trends (1999-2013) has been conducted at the site in collaboration with activities related to the 2013 Southeast Atmosphere Study (SAS) at Look Rock and other southeastern US locations. Key findings from these trend studies include the observation that primary pollutant levels have consistently tracked emissions reductions from EGUs and other primary sources in the region but reductions in secondary pollutants such as particulate sulfate and, specifically, ozone have been smaller compared to reductions in primary emissions. Organic carbonaceous material (OM) remains a major contributor (30-40% in the period 2009-2013) to fine particulate mass at the site, as confirmed by ACSM measurements at the site in 2013. A large portion (65-85%) of carbon in OM derives from modern carbon sources based on 14C measurements. Important parameters affecting ozone levels, fine mass and visibility also include the specific diurnal meteorology at this ridge-top site, its location in a predominantly mixed-deciduous forest, and the presence of primary sources of precursors at distances of 50-500 km from the site in all directions.

  18. Search for ultraviolet emission lines from a hot gaseous halo in the edge-on galaxy NGC 4244

    NASA Technical Reports Server (NTRS)

    Deharveng, J.-M.; Joubert, M.; Bixler, J.; Bowyer, S.; Malina, R.

    1986-01-01

    Short and long wavelength IUE spectra of the halo region in the edge-on galaxy NGC 4244 are analyzed in order to identify evidence of line emission at the level of 0.000001 ergs per cu cm sr/s. Features are found at 1245 A and 1402 A, having peaks four times greater than the rms intensity fluctuations of nearby spectra. The spectral features are identified with semi-forbidden N V, semi-forbidden S IV at 1240 A, and Si IV and semi-forbidden O IV multiplets at 1400 A, respectively. The appearance of high-peak features and the lack of astrophysically important lines in the sample are evidence of a gas near T = 10 exp 5.2 and emission measure (EM) equal to about 0.000001 pc. However, the case for the existence of such a gas is weakened due to the existence of two other similarly sized features with no identifiable astrophysical origin and the extremely faint nature of the candidate features. The assumed upper limit for the line intensities in NGC 4244 leads to the conclusion that at T less than 100,000 K any emitting gas is either highly clumped or has a p/k value of less than 1000 per cu cm K. It is suggested that if the observed low level features in the short wavelength spectrum are real, the temperature and emission measures allow for a single component gas in the halo of NGC 4244, and are in agreement with those derived by Paresce et al. (1983).

  19. Investigation of gaseous and particulate emissions from various marine vessel types measured on the banks of the Elbe in Northern Germany

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Klimach, T.; Borrmann, S.

    2013-04-01

    Measurements of the ambient aerosol, various trace gases and meteorological quantities using a mobile laboratory (MoLa) were performed on the banks of the Lower Elbe in an emission control area (ECA) which is passed by numerous private and commercial marine vessels reaching and leaving the port of Hamburg, Germany. From 25-29 April 2011 a total of 178 vessels were probed at a distance of about 0.8-1.2 km with high temporal resolution. 139 ship emission plumes were of sufficient quality to be analyzed further and to determine emission factors (EFs). Concentrations of aerosol number and mass as well as polycyclic aromatic hydrocarbons (PAH) and black carbon were measured in PM1 and size distribution instruments covered the diameter range from 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase species analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) in the air and a weather station provided wind, precipitation, solar radiation data and other quantities. Together with ship information for each vessel obtained from Automatic Identification System (AIS) broadcasts a detailed characterization of the individual ship types and of features affecting gas and particulate emissions is provided. Particle number EFs (average 2.6e+16 # kg-1) and PM1 mass EFs (average 2.4 g kg-1) tend to increase with the fuel sulfur content. Observed PM1 composition of the vessel emissions was dominated by organic matter (72%), sulfate (22%) and black carbon (6%) while PAHs only account for 0.2% of the submicron aerosol mass. Measurements of gaseous components showed an increase of SO2 (average EF: 7.7 g kg-1) and NOx (average EF: 53 g kg-1) while O3 decreased when a ship plume reached the sampling site. The particle number size distributions of the vessels are generally characterized by a bimodal size distribution, with the nucleation mode in the 10-20 nm diameter

  20. Investigation of gaseous and particulate emissions from various marine vessel types measured on the banks of the Elbe in Northern Germany

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Klimach, T.; Borrmann, S.

    2012-08-01

    Measurements of the ambient aerosol, various trace gases and meteorological parameters using a mobile laboratory (MoLa) were performed on the banks of the Lower Elbe in an emission control area (ECA) which is passed by numerous private and commercial marine vessels reaching and leaving the port of Hamburg, Germany. From 25-30 April 2011 a total of 178 vessels were probed at a distance of about 0.8-2 km with high temporal resolution. 139 ship emission plumes were of sufficient quality to be analyzed further and to determine emission factors (EFs). Concentrations of aerosol number and mass as well as polycyclic aromatic hydrocarbons (PAH) and black carbon were measured in PM1 and size distribution instruments covered the size diameter range from 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase species analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) in the air and a weather station provided wind, precipitation, solar radiation and other parameters. Together with ship information for each vessel obtained from Automatic Identification System (AIS) broadcasts a detailed characterization of the individual ship types and of features affecting gas and particulate emissions is provided. Particle number EFs (average 2.6×1016 # kg -1) and PM1 mass EFs (average 2.4 g kg -1) positively correlate with the fuel sulfur content and depend on the engine type and performance. Observed PM1 composition of the vessel emissions was dominated by organic matter (72%), sulfate (22%) and black carbon (6%) while PAHs only account for 0.2% of the submicron aerosol mass. Measurements of gaseous components showed an increase of SO2 (average EF: 7.7 g kg-1) and NOx (average EF: 53 g kg-1) while O3 decreased when a ship plume reached the sampling site. The particle number size distributions of the vessels are generally characterized by a bimodal size

  1. GASEOUS SCINTILLATION COUNTER

    DOEpatents

    Eggler, C.; Huddleston, C.M.

    1959-04-28

    A gaseous excitation counter for detecting the presence amd measuring the energy of subatomic particles and electromagnetic radiation is described. The counter includes a gas-tight chamber filled with an elemental gas capable of producing ultra-violet excitation quanta when irradiated with subatomic particles and electromagnetic radiation. The gas has less than one in a thousand parts ultra-violet absorbing contamination. When nuclear radiation ps present the ultra-violet light produced by the gas strikes a fluorescent material within the counter, responsive to produce visible excitation quanta, and photo-sensitive counting means detect the visible emission.

  2. Emission Characteristics and Stability of Laser Ion Sources

    SciTech Connect

    Krasa, J.; Velyhan, A.; Krousky, E.; Laska, L.; Rohlena, K.; Jungwirth, K.; Ullschmied, J.; Lorusso, A.; Velardi, L.; Nassisi, V.; Czarnecka, A.; Ryc, L.; Parys, P.; Wolowksi, J.

    2010-10-13

    A new classification of laser ion sources concerning their pulse-to-pulse reproducibility in the ion emission is proposed. In particular, we distinguish between plasmas according to the electron distribution changing its characteristics at a laser intensity threshold of 10{sup 14} W/cm{sup 2}. Well reproducible continuous pulsed ion currents are typical for the intensity below the threshold. In contrast to this plasma the 'two-temperature' plasma arising for the intensity above this threshold shows not only a separation of charges in space and time but it also shows irregular and intense outbursts of ions similar to a self pulsing instability leading to a chaos. The sequence of fast ion outbursts visible on time-of-flight spectra is sensitive to details of non-linear interaction of the sub-nanosecond laser beam with the generated plasma.

  3. Photodissociation of gaseous CH3COSH at 248 nm by time-resolved Fourier-transform infrared emission spectroscopy: Observation of three dissociation channels

    NASA Astrophysics Data System (ADS)

    Hu, En-Lan; Tsai, Po-Yu; Fan, He; Lin, King-Chuen

    2013-01-01

    Upon one-photon excitation at 248 nm, gaseous CH3C(O)SH is dissociated following three pathways with the products of (1) OCS + CH4, (2) CH3SH + CO, and (3) CH2CO + H2S that are detected using time-resolved Fourier-transform infrared emission spectroscopy. The excited state 1(nO, π*CO) has a radiative lifetime of 249 ± 11 ns long enough to allow for Ar collisions that induce internal conversion and enhance the fragment yields. The rate constant of collision-induced internal conversion is estimated to be 1.1 × 10-10 cm3 molecule-1 s-1. Among the primary dissociation products, a fraction of the CH2CO moiety may undergo further decomposition to CH2 + CO, of which CH2 is confirmed by reaction with O2 producing CO2, CO, OH, and H2CO. Such a secondary decomposition was not observed previously in the Ar matrix-isolated experiments. The high-resolution spectra of CO are analyzed to determine the ro-vibrational energy deposition of 8.7 ± 0.7 kcal/mol, while the remaining primary products with smaller rotational constants are recognized but cannot be spectrally resolved. The CO fragment detected is mainly ascribed to the primary production. A prior distribution method is applied to predict the vibrational distribution of CO that is consistent with the experimental findings.

  4. Croton megalocarpus oil-fired micro-trigeneration prototype for remote and self-contained applications: experimental assessment of its performance and gaseous and particulate emissions

    PubMed Central

    Wu, Dawei; Roskilly, Anthony P.; Yu, Hongdong

    2013-01-01

    According to the International Energy Agency's World Energy Outlook 2011, 60 per cent of the population in Africa, some 587 million people, mostly in sub-Saharan Africa, lacked access to electricity in 2009. We developed a 6.5 kWe micro-trigeneration prototype, on the basis of internal combustion engine with pure Croton megalocarpus oil (CMO) fuelling, which configures a distributed energy system to generate power, heating and cooling from a single sustainable fuel source for remote users. Croton megalocarpus is an indigenous tree in East and South Africa which has recently attracted lots of interests as a biofuel source because of its high oil-yield rate. The direct and local use of CMO, instead of CMO biodiesel converted by the transesterification process, minimizes the carbon footprints left behind because of the simple fuel production of CMO. The experimental assessment proves that the prototype fuelled with CMO achieves similar efficiency as with diesel. Also, with the elevation of the oil injection temperature, the gaseous and particulate emissions of CMO could be ameliorated to some extent as improvement of the atomization in the spray and the combustion in the engine cylinder. PMID:24427514

  5. Croton megalocarpus oil-fired micro-trigeneration prototype for remote and self-contained applications: experimental assessment of its performance and gaseous and particulate emissions.

    PubMed

    Wu, Dawei; Roskilly, Anthony P; Yu, Hongdong

    2013-02-01

    According to the International Energy Agency's World Energy Outlook 2011, 60 per cent of the population in Africa, some 587 million people, mostly in sub-Saharan Africa, lacked access to electricity in 2009. We developed a 6.5 kWe micro-trigeneration prototype, on the basis of internal combustion engine with pure Croton megalocarpus oil (CMO) fuelling, which configures a distributed energy system to generate power, heating and cooling from a single sustainable fuel source for remote users. Croton megalocarpus is an indigenous tree in East and South Africa which has recently attracted lots of interests as a biofuel source because of its high oil-yield rate. The direct and local use of CMO, instead of CMO biodiesel converted by the transesterification process, minimizes the carbon footprints left behind because of the simple fuel production of CMO. The experimental assessment proves that the prototype fuelled with CMO achieves similar efficiency as with diesel. Also, with the elevation of the oil injection temperature, the gaseous and particulate emissions of CMO could be ameliorated to some extent as improvement of the atomization in the spray and the combustion in the engine cylinder. PMID:24427514

  6. Characteristics of smoke emissions from biomass fires of the Amazon region - BASE-A experiment

    NASA Technical Reports Server (NTRS)

    Ward, Darold E.; Setzer, Alberto W.; Kaufman, Yoram J.; Rasmussen, Rei A.

    1991-01-01

    The Biomass Burning Airborne and Spaceborne Experiment-Amazonia was designed for study of both aerosol and gaseous emissions from fires using an airborne sampling platform. The emission factors for combustion products from four fires suggest that the proportion of carbon released in the form of CO2 is higher than for fires of logging which has been burned in the western U.S. Combustion efficiency was of the order of 97 percent for the Amazonian test fire and 86-94 percent for deforestation fires. The inorganic content of particles from tropical fires are noted to be different from those of fires in the U.S.

  7. Gaseous Detectors

    NASA Astrophysics Data System (ADS)

    Titov, Maxim

    Since long time, the compelling scientific goals of future high-energy physics experiments were a driving factor in the development of advanced detector technologies. A true innovation in detector instrumentation concepts came in 1968, with the development of a fully parallel readout for a large array of sensing elements - the Multi-Wire Proportional Chamber (MWPC), which earned Georges Charpak a Nobel prize in physics in 1992. Since that time radiation detection and imaging with fast gaseous detectors, capable of economically covering large detection volumes with low mass budget, have been playing an important role in many fields of physics. Advances in photolithography and microprocessing techniques in the chip industry during the past decade triggered a major transition in the field of gas detectors from wire structures to Micro-Pattern Gas Detector (MPGD) concepts, revolutionizing cell-size limitations for many gas detector applications. The high radiation resistance and excellent spatial and time resolution make them an invaluable tool to confront future detector challenges at the next generation of colliders. The design of the new micro-pattern devices appears suitable for industrial production. Novel structures where MPGDs are directly coupled to the CMOS pixel readout represent an exciting field allowing timing and charge measurements as well as precise spatial information in 3D. Originally developed for the high-energy physics, MPGD applications have expanded to nuclear physics, photon detection, astroparticle and neutrino physics, neutron detection, and medical imaging.

  8. Characterization of gaseous odorous emissions from a rendering plant by GC/MS and treatment by biofiltration.

    PubMed

    Anet, Benoît; Lemasle, Marguerite; Couriol, Catherine; Lendormi, Thomas; Amrane, Abdeltif; Le Cloirec, Pierre; Cogny, Gilles; Fillières, Romain

    2013-10-15

    This research focuses on the identification and quantification of odorous components in rendering plant emissions by GC/MS and other analytical methods, as well as the description of phenomena occurring in biofilter in order to improve the removal efficiency of industrial biofilters. Among the 36 compounds quantified in the process air stream, methanethiol, isopentanal and hydrogen sulfide, presented the major odorous contributions according to their high concentrations, generally higher than 10 mg m(-3), and their low odorous detection thresholds. The elimination of such component mixtures by biofiltration (Peat packing material, EBRT: 113 s) was investigated and revealed that more than 83% of hydrogen sulfide and isopentanal were removed by biofilter. Nevertheless, the incomplete degradation of such easily degradable pollutants suggested inappropriate conditions as lack of nutrients and acidic pH. These inadequate conditions could explain the lack of performance, especially observed on methanethiol (53% of RE) and the production of oxygenated and sulfur by-products by the biofilter itself. PMID:23895910

  9. Gaseous NO2 effects on epidermis and stomata related physiochemical characteristics of hybrid poplar leaves: chemical elements composition, stomatal functions, photosynthesis and respiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mechanisms controlling effects of gaseous nitrogen dioxide on epidermis and stomata dynamics, and photosynthesis and respirations processes are still not fully understood. In this study, we used poplar as a model plant and investigated the effects of gaseous nitrogen dioxide (4 microliters per lite...

  10. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: the influence of zeolite chemical surface characteristics.

    PubMed

    Alejandro, Serguei; Valdés, Héctor; Manéro, Marie-Hélène; Zaror, Claudio A

    2014-06-15

    In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity. PMID:24794812

  11. The effects of gaseous bubble composition and gap distance on the characteristics of nanosecond discharges in distilled water

    NASA Astrophysics Data System (ADS)

    Hamdan, Ahmad; Cha, Min Suk

    2016-06-01

    Electric discharge in liquids with bubbles can reduce the energy consumption, which increases treatment efficiency. We present an experimental study of nanosecond discharges in distilled water bubbled with the monoatomic gas argon and with the polyatomic gases methane, carbon dioxide, and propane. We monitor the time evolution of the voltage and current waveforms, and calculate the injected charges to characterize the discharge. We establish a relationship between the injected charges and the shape of the plasma by time-resolved imaging to find that increasing the size of the gap reduces the injected charges. Moreover, we determine the plasma characteristics, including electron density, excitation temperatures (for atoms and ions), and rotational temperature of the OH and C2 radicals found in the plasma. Our space- and time-averaged measurements allow us to propose a spatial distribution of the plasma that is helpful for understanding the plasma dynamics necessary to develop and optimize applications based on nanosecond discharges in bubbled liquids.

  12. Surface slope characteristics from Thermal Emission Spectrometer emission phase function observations

    NASA Astrophysics Data System (ADS)

    Edwards, C. S.; Bandfield, J. L.; Christensen, P. R.

    2006-12-01

    It is possible to obtain surface roughness characteristics, by measuring a single surface from multiple emission angles and azimuths in the thermal infrared. Surfaces will have different temperatures depending on their orientation relative to the sun. A different proportion of sunlit versus shaded surfaces will be in the field of view based on the viewing orientation, resulting in apparent temperature differences. This difference in temperature can be utilized to calculate the slope characteristics for the observed area. This technique can be useful for determining surface slope characteristics not resolvable by orbital imagery. There are two main components to this model, a surface DEM, in this case a synthetic, two dimensional sine wave surface, and a thermal model (provided by H. Kieffer). Using albedo, solar longitude, slope, azimuth, along with several other parameters, the temperature for each cell of the DEM is calculated using the thermal model. A temperature is then predicted using the same observation geometries as the Thermal Emission Spectrometer (TES) observations. A temperature difference is calculated for the two complementary viewing azimuths and emission angles from the DEM. These values are then compared to the observed temperature difference to determine the surface slope. This method has been applied to TES Emission Phase Function (EPF) observations for both the spectrometer and bolometer data, with a footprint size of 10s of kilometers. These specialized types of TES observations measure nearly the same surface from several angles. Accurate surface kinetic temperatures are obtained after the application of an atmospheric correction for the TES bolometer and/or spectrometer. Initial results include an application to the northern circumpolar dunes. An average maximum slope of ~33 degrees has been obtained, which makes physical sense since this is near the angle of repose for sand sized particles. There is some scatter in the data from separate

  13. Characteristics of mesospheric optical emissions produced by lighting discharges

    NASA Astrophysics Data System (ADS)

    Veronis, Georgios; Pasko, Victor P.; Inan, Umran S.

    1999-06-01

    A new two-dimensional cylindrically symmetric electromagnetic model of the lightning-ionosphere interaction includes effects of both the lightning radiated electromagnetic pulses (EMP) and the quasi-electrostatic (QE) fields, thus allowing effective studies of lightning-ionosphere interactions on time scales ranging from several microseconds to tens of milliseconds. The temporal and spatial evolution of the electric field, lower ionospheric electron density, and optical emissions calculated with the new model are used to investigate theoretically the effects of the lightning return stroke current waveform (i.e., the current rise and fall timescales) and of the observational geometry on the optical signals observed with a photometer. For typical lightning discharges of ~100 μs duration the ionospheric response is dominated by the EMP-induced heating leading to the highly transient and laterally expanding optical flashes known as elves. The optical signal characteristics are found to be highly sensitive to both the observational geometry and the current waveform. The onset delay with respect to the lighting discharge, the duration, and the peak magnitude of optical emissions are highly dependent on the elevation and azimuth angles of field of view of individual photometric pixels. The shape of the optical signal clearly reflects the source current waveform. For a waveshape with risetime of ~50 μs or longer a double-pulse shape of the photometric signal is observed. For cloud to ground lightning discharges of ~1 ms duration removing substantial amount of charge (i.e., ~100 C from 10 km altitude), heating and ionization changes induced by the QE field lead to the mesospheric luminous glows with lateral extent <100 km, referred to as sprites.

  14. Performance and emissions characteristics of aqueous alcohol fumes in a DI diesel engine

    NASA Technical Reports Server (NTRS)

    Heisey, J. B.; Lestz, S. S.

    1981-01-01

    A single cylinder DI Diesel engine was fumigated with ethanol and methanol in amounts up to 55% of the total fuel energy. The effects of aqueous alcohol fumigation on engine thermal efficiency, combustion intensity and gaseous exhaust emissions were determined. Assessment of changes in the biological activity of raw particulate and its soluble organic fraction were also made using the Salmonella typhimurium test. Alcohol fumigation improved thermal efficiency slightly at moderate and heavy loads, but increased ignition delay at all operating conditions. Carbon monoxide and unburned hydrocarbon emission generally increased with alcohol fumigation and showed no dependence on alcohol type or quality. Oxide of nitrogen emission showed a strong dependence on alcohol quality; relative emission levels decreased with increasing water content of the fumigant. Particulate mass loading rates were lower for ethanol fueled conditions. However, the biological activity of both the raw particulate and its soluble organic fraction was enhanced by ethanol fumigation at most operating conditions.

  15. Explosion bomb measurements of ethanol-air laminar gaseous flame characteristics at pressures up to 1.4 MPa

    SciTech Connect

    Bradley, D.; Lawes, M.; Mansour, M.S.

    2009-07-15

    The principal burning characteristics of a laminar flame comprise the fuel vapour pressure, the laminar burning velocity, ignition delay times, Markstein numbers for strain rate and curvature, the stretch rates for the onset of flame instabilities and of flame extinction for different mixtures. With the exception of ignition delay times, measurements of these are reported and discussed for ethanol-air mixtures. The measurements were in a spherical explosion bomb, with central ignition, in the regime of a developed stable, flame between that of an under or over-driven ignition and that of an unstable flame. Pressures ranged from 0.1 to 1.4 MPa, temperatures from 300 to 393 K, and equivalence ratios were between 0.7 and 1.5. It was important to ensure the relatively large volume of ethanol in rich mixtures at high pressures was fully evaporated. The maximum pressure for the measurements was the highest compatible with the maximum safe working pressure of the bomb. Many of the flames soon became unstable, due to Darrieus-Landau and thermo-diffusive instabilities. This effect increased with pressure and the flame wrinkling arising from the instabilities enhanced the flame speed. Both the critical Peclet number and the, more rational, associated critical Karlovitz stretch factor were evaluated at the onset of the instability. With increasing pressure, the onset of flame instability occurred earlier. The measured values of burning velocity are expressed in terms of their variations with temperature and pressure, and these are compared with those obtained by other researchers. Some comparisons are made with the corresponding properties for iso-octane-air mixtures. (author)

  16. Gaseous emissions, growth performance and pork quality of pigs housed in deep-litter system compared to concrete-floor system.

    PubMed

    Zhou, Chuanshe; Hu, Jinjie; Zhang, Bin; Tan, Zhiliang

    2015-04-01

    This study measured gaseous emissions, growth performance and pork quality in a deep-litter system and concrete-floor system. Three hundred and twenty weaned piglets with an average body weight (BW) of 6.0 ± 0.3 kg were assigned randomly into three treatments. Treatments 1 and 2 included four pens with 20 pigs for each pen respectively in the deep-litter system, and the ratio of sawdust to chaff was 5:5 and 3:7 for treatments 1 and 2 respectively, the probiotics inoculated into the fermentation bedding for both treatments were composed of Saccharomycetes, Bacillus subtilis and Actinomycetes; treatment 3 was the conventional concrete-floor system including eight pens with 20 pigs for each pen. The concentration of NH3 and CO2 in the deep-litter system was significantly (P < 0.001) lower than that in the concrete-floor system. The ratio of feed to gain for pigs raised in the deep-litter system was significantly (P < 0.05) lower than that for pigs housed in the concrete-floor system. The carcass weight and length, color score and rate of cooking meat for pork from the deep-litter system were significantly (P < 0.05) higher than those from the concrete-floor system. Results indicate that pigs raised in the deep-litter system had some animal welfare improvements and an odor nuisance reduction; in the meantime, pork quality also improved from the deep-litter system compared to the pigs housed in the concrete-floor system. PMID:25491590

  17. Photodissociation of gaseous CH{sub 3}COSH at 248 nm by time-resolved Fourier-transform infrared emission spectroscopy: Observation of three dissociation channels

    SciTech Connect

    Hu, En-Lan; Tsai, Po-Yu; Fan, He; Lin, King-Chuen

    2013-01-07

    Upon one-photon excitation at 248 nm, gaseous CH{sub 3}C(O)SH is dissociated following three pathways with the products of (1) OCS + CH{sub 4}, (2) CH{sub 3}SH + CO, and (3) CH{sub 2}CO + H{sub 2}S that are detected using time-resolved Fourier-transform infrared emission spectroscopy. The excited state {sup 1}(n{sub O}, {pi}{sup *}{sub CO}) has a radiative lifetime of 249 {+-} 11 ns long enough to allow for Ar collisions that induce internal conversion and enhance the fragment yields. The rate constant of collision-induced internal conversion is estimated to be 1.1 Multiplication-Sign 10{sup -10} cm{sup 3} molecule{sup -1} s{sup -1}. Among the primary dissociation products, a fraction of the CH{sub 2}CO moiety may undergo further decomposition to CH{sub 2}+ CO, of which CH{sub 2} is confirmed by reaction with O{sub 2} producing CO{sub 2}, CO, OH, and H{sub 2}CO. Such a secondary decomposition was not observed previously in the Ar matrix-isolated experiments. The high-resolution spectra of CO are analyzed to determine the ro-vibrational energy deposition of 8.7 {+-} 0.7 kcal/mol, while the remaining primary products with smaller rotational constants are recognized but cannot be spectrally resolved. The CO fragment detected is mainly ascribed to the primary production. A prior distribution method is applied to predict the vibrational distribution of CO that is consistent with the experimental findings.

  18. Results from Mobile Lab Measurements Obtained in the Barnett Shale with Emphasis on Methane and Gaseous Mercury Emissions (Fort Worth, TX)

    NASA Astrophysics Data System (ADS)

    Laine, P. L.; Lan, X.; Anderson, D.; Talbot, R. W.

    2013-12-01

    Our work is part of a comprehensive analysis conducted through a collaboration of ground based measurements and airborne measurements with several research groups in order to gain a better understanding of methane and mercury emissions in the Barnett Shale. It's a vast rock formation that sits in the 5,000 square miles surrounding the Fort Worth area. To get the gas to market requires an underground highway of pipelines and compression stations. Texas state records show that since 2000 the number of gas compressors in the Barnett Shale has tripled (from a few hundred to 1,300), and they're ever infringing on populated areas. Recent preliminary data reported by Pétron et al. and Tollefson et al. (from the natural-gas operations in Denver-Julesburg Basin) point to CH4 loss from the process of 4-8%, not including additional losses in the pipeline and distribution system. Additionally, Howarth et al. have conducted a comprehensive analysis of greenhouse gases (methane, in particular) emitted from shale gas as a result of hydraulic fracturing and they estimate up to 8% of all natural gas mined from shale formations leaks to the atmosphere. Not only is this cause for alarm due to the global warming potential of methane, but we would expect similar losses of additional (potentially harmful) gases, i.e., atmospheric Hg, from the extraction systems. These preliminary findings are higher than the current U.S. Environment Protection Agency (EPA) leakage estimate of 2.3 percent. Our strategy employs the use of our mobile laboratory, a four door Chevrolet Silverado pickup truck with a camper shell, outfitted with trace gas instrumentation including a Picarro G2132i and a Tekran 2537 mercury analyzer. The Picarro cavity ring down instrument has high precision and accuracy H2O, CO2, CH4, and 13δC in CH4 and CO2 with very little drift due to precise temperature and pressure controls. The Tekran mercury analyzer allows for accurate total gaseous mercury measurements via

  19. Chemical characteristics of Siberian boreal forest fire emissions

    NASA Astrophysics Data System (ADS)

    Engling, G.; Popovicheva, O.; Fan, T. S.; Eleftheriadis, K.; Diapouli, E.; Kozlov, V.

    2014-12-01

    Smoke emissions from Siberian boreal forest fires exert critical impacts on the aerosol/climate system of subarctic regions and the Arctic. It is, therefore, crucial to assess the ability of such particles to absorb/scatter incoming solar radiation as well as act as cloud condensation nuclei, which is closely linked to the physical and chemical aerosol properties. However, observations of Siberian wildfire emissions are limited, and no systematic database of smoke particle properties is available for this region to date. As part of this study, ambient aerosol samples were collected during two smoke episodes in Tomsk, Siberia, in the summers of 2012 and 2013. In addition, the chemical composition and optical properties of smoke particles derived from the combustion of typical Siberian fuels, including pine wood and debris, were determined during chamber burn experiments in a large aerosol/combustion chamber under controlled combustion conditions representative of wildfires and prescribed burns. Detailed multi-component characterization of individual particles and bulk properties was accomplished with a suite of techniques, including various types of chromatography, microscopy, spectroscopy, and thermo-optical analysis. Individual particle analysis by SEM-EDX combined with cluster analysis revealed characteristic smoke structural components and major types of particles, which allowed to discriminate between flaming and smoldering regimes, reflected in specific morphological and chemical microstructure. The physicochemical properties representing the combustion phase (smoldering versus flaming) and the degree of processing (fresh versus aged) were assessed in the ambient aerosol based on the chamber burn results. For instance, some chemical transformation (aging of smoke particles) was noticed over a period of two days in the absence of sun light in the combustion chamber for certain chemical species, while the molecular tracer levoglucosan appeared to be rather

  20. Diffusion-based process for carbon dioxide uptake and isoprene emission in gaseous/aqueous two-phase photobioreactors by photosynthetic microorganisms.

    PubMed

    Bentley, Fiona K; Melis, Anastasios

    2012-01-01

    Photosynthesis for the generation of fuels and chemicals from cyanobacteria and microalgae offers the promise of a single host organism acting both as photocatalyst and processor, performing sunlight absorption and utilization, as well as CO(2) assimilation and conversion into product. However, there is a need to develop methods for generating, sequestering, and trapping such bio-products in an efficient and cost-effective manner that is suitable for industrial scale-up and exploitation. A sealed gaseous/aqueous two-phase photobioreactor was designed and applied for the photosynthetic generation of volatile isoprene (C(5)H(8)) hydrocarbons, which operates on the principle of spontaneous diffusion of CO(2) from the gaseous headspace into the microalgal or cyanobacterial-containing aqueous phase, followed by photosynthetic CO(2) assimilation and isoprene production by the transgenic microorganisms. Volatile isoprene hydrocarbons were emitted from the aqueous phase and were sequestered into the gaseous headspace. Periodic replacement (flushing) of the isoprene (C(5)H(8)) and oxygen (O(2)) content of the gaseous headspace with CO(2) allowed for the simultaneous harvesting of the photoproducts and replenishment of the CO(2) supply in the gaseous headspace. Reduction in practice of the gaseous/aqueous two-phase photobioreactor is offered in this work with a fed-batch and a semi-continuous culturing system using Synechocystis sp. PCC 6803 heterologously expressing the Pueraria montana (kudzu) isoprene synthase (IspS) gene. Constitutive isoprene production was observed over 192 h of experimentation, coupled with cyanobacterial biomass accumulation. The diffusion-based process in gaseous/aqueous two-phase photobioreactors has the potential to be applied to other high-value photosynthetically derived volatile molecules, emanating from a variety of photosynthetic microorganisms. PMID:21830206

  1. 47 CFR 2.201 - Emission, modulation, and transmission characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... frequency emissions, continuous wave and pulse radars, etc. (1) No information transmitted N (2) Telegraphy..., telemetry, telecommand D (6) Telephony (including sound broadcasting) E (7) Television (video) F...

  2. Field emission characteristics from graphene on hexagonal boron nitride

    SciTech Connect

    Yamada, Takatoshi; Masuzawa, Tomoaki; Ebisudani, Taishi; Okano, Ken; Taniguchi, Takashi

    2014-06-02

    An attempt has been made to utilize uniquely high electron mobility of graphene on hexagonal boron nitride (h-BN) to electron emitter. The field emission property of graphene/h-BN/Si structure has shown enhanced threshold voltage and emission current, both of which are key to develop novel vacuum nanoelectronics devices. The field emission property was discussed along with the electronic structure of graphene investigated by Fowler-Nordheim plot and ultraviolet photoelectron spectroscopy. The result suggested that transferring graphene on h-BN modified its work function, which changed field emission mechanism. Our report opens up a possibility of graphene-based vacuum nanoelectronics devices with tuned work function.

  3. Emissions characteristics of Military Helicopter Engines Fueled with JP-8 and a Fischer-Tropsch Fuel

    SciTech Connect

    Corporan, E.; DeWitt, M.; Klingshirn, Christopher D; Striebich, Richard; Cheng, Mengdawn

    2010-01-01

    The rapid growth in aviation activities and more stringent U.S. Environmental Protection Agency regulations have increased concerns regarding aircraft emissions, due to their harmful health and environmental impacts, especially in the vicinity of airports and military bases. In this study, the gaseous and particulate-matter emissions of two General Electric T701C engines and one T700 engine were evaluated. The T700 series engines power the U.S. Army's Black Hawk and Apache helicopters. The engines were fueled with standard military JP-8 fuel and were tested at three power settings. In addition, one of the T701C engines was operated on a natural-gas-derived Fischer-Tropsch synthetic paraffinic kerosene jet fuel. Test results show that the T701C engine emits significantly lower particulate-matter emissions than the T700 for all conditions tested. Particulate-matter mass emission indices ranged from 0.2-1.4 g/kg fuel for the T700 and 0.2-0.6 g/kg fuel for the T701C. Slightly higher NOx and lower CO emissions were observed for the T701C compared with the T700. Operation of the T701C with the Fischer-Tropsch fuel rendered dramatic reductions in soot emissions relative to operation on JP-8, due primarily to the lack of aromatic compounds in the alternative fuel. The Fischer-Tropsch fuel also produced smaller particles and slight reductions in CO emissions.

  4. The emission characteristics of uranium hexafluoride at high temperatures

    NASA Technical Reports Server (NTRS)

    Krascella, N. L.

    1976-01-01

    Relative emission measurements were made for UF6/Argon mixtures heated in a plasma torch over a range of temperatures from 800 to about 3600 K over a wavelength range from 80 to 600 nm. Total pressures were varied from 1 to approximately 1.7 atm. Similarly absorption measurements were carried out in the visible region from 420 to 580 nm over a temperature range from about 1000 to 1800 K. Total pressure for these measurements was 1.0 atm. The emission results exhibited relatively no emission at wavelengths below 250 nm over the range of temperatures investigated. At temperatures in excess of 1800 K an additional emission band centered at 310 nm appears and becomes more well defined at higher temperatures. Essentially no pressure effect was observed with respect to emission at pressures up to 1.7 atm.

  5. [Investigation of emission characteristics for light duty vehicles with a portable emission measurement system].

    PubMed

    Wang, Hai-Kun; Fu, Li-Xin; Zhou, Yu; Lin, Xin; Chen, Ai-Zhong; Ge, Wei-hu; Du, Xuan

    2008-10-01

    Emission from 7 typical light-duty vehicles under actual driving conditions was monitored using a portable emission measurement system to gather data for characterization of the real world vehicle emission in Shenzhen, including the effects of driving modes on vehicle emission, comparison of fuel consumption based emission factors (g x L(-1) with mileage based emission factors (g x km(-1)), and the average emission factors of the monitored vehicles. The acceleration and deceleration modes accounted for 66.7% of total travel time, 80.3% of traveling distance and 74.6%-79.2% of vehicle emission; the acceleration mode contributed more than other driving modes. The fuel based emission factors were less dependent on the driving speed; they may be utilized in building macro-scale vehicle emission inventory with smaller sensitivity to the vehicle driving conditions. The effect of vehicle technology on vehicle emission was significant; the emission factors of CO, HC and NO(x) of carbureted vehicles were 19.9-20.5, 5.6-26.1 and 1.8-2.0 times the more advanced vehicles of Euro II, respectively. Using the ECE + EUDC driving cycle would not produce the desired real-world emission rates of light duty vehicles in a typical Chinese city. PMID:19143403

  6. (π−1) → (π−1), (π−1) emission spectra of chlorofluorobenzene cations in the gaseous phase and their lifetimes in the (0o) states

    USGS Publications Warehouse

    Maier, John Paul; Marthaler, O.; Mohraz, Manijeh; Shiley, R.H.

    1980-01-01

    The radiative decay of seventeen electronically excited chlorofluorobenzene cations in the gaseous phase has been detected. The reported emission spectra, which have been obtained using low energy electron beam excitation, are assigned to the B(??-1 ??? X(??-1 electronic transitions of these cations on the basis of their Ne(I) photoelectron spectra. In another sixteen chloroflourobenzene cations, the B ??? X radiative decay could not be detected, from which is inferred that the B states are now associated with Cl 3p(??-1 ionisation processes. The lifetimes of the studied cations in the lowest vibrational levels of the B(??-1 state have been measured. ?? 1980.

  7. Hydrogen sensing characteristics from carbon nanotube field emissions.

    PubMed

    Dong, Changkun; Luo, Haijun; Cai, Jianqiu; Wang, Fuquan; Zhao, Yangyang; Li, Detian

    2016-03-14

    An innovative hydrogen sensing concept is demonstrated based on the field emission from multi-walled carbon nanotubes, where the low emission currents rise in proportion to hydrogen partial pressures above 10(-9) Torr. Experimental and first principles studies reveal that the sensing mechanism is attributed to the effective work function reduction from dissociative hydrogen chemisorption. The embedded Ni catalyst would assist both the hydrogen dissociation and work function reduction. This technique is promising to build miniature low cost hydrogen sensors for multiple applications. This work is valuable for studies of nanocarbon-gas reaction mechanisms and the work function properties in adsorption related applications, including field emission, hydrogen storage, energy cells, and gas sensing. PMID:26890686

  8. Hydrogen sensing characteristics from carbon nanotube field emissions

    NASA Astrophysics Data System (ADS)

    Dong, Changkun; Luo, Haijun; Cai, Jianqiu; Wang, Fuquan; Zhao, Yangyang; Li, Detian

    2016-03-01

    An innovative hydrogen sensing concept is demonstrated based on the field emission from multi-walled carbon nanotubes, where the low emission currents rise in proportion to hydrogen partial pressures above 10-9 Torr. Experimental and first principles studies reveal that the sensing mechanism is attributed to the effective work function reduction from dissociative hydrogen chemisorption. The embedded Ni catalyst would assist both the hydrogen dissociation and work function reduction. This technique is promising to build miniature low cost hydrogen sensors for multiple applications. This work is valuable for studies of nanocarbon-gas reaction mechanisms and the work function properties in adsorption related applications, including field emission, hydrogen storage, energy cells, and gas sensing.

  9. Emission characteristics of snow and ice in the microwave range

    NASA Technical Reports Server (NTRS)

    Meier, M. F.; Edgerton, A. T.

    1971-01-01

    Some results are presented of a two year investigation on microwave emissions from snow. Included in the investigation were: theoretical studies; laboratory measurements of electrical properties of snow and similar materials; numerical modelling of hypothetical and real snowpacks; analysis of microwave data obtained on everflights; and quantative measurements of natural and artificial snowpacks made in the field. Results indicate that a fairly simple combination of microwave polarizations and frequencies can ultimately be used to monitor the water equivalent and free-water content as well as the distribution of snow. This understanding may also shed light on the physics of microwave emission from other wet, granular, layered media.

  10. Method of improving field emission characteristics of diamond thin films

    DOEpatents

    Krauss, Alan R.; Gruen, Dieter M.

    1999-01-01

    A method of preparing diamond thin films with improved field emission properties. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display.

  11. Method of improving field emission characteristics of diamond thin films

    DOEpatents

    Krauss, A.R.; Gruen, D.M.

    1999-05-11

    A method of preparing diamond thin films with improved field emission properties is disclosed. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display. 3 figs.

  12. Influence of the gaseous form on the precursor heating layer of a laser-supported detonation wave using half self-emission half shadowgraph visualization

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Michigami, Keisuke; Ofoso, Joseph; Komursaki, Kimiya

    2012-10-01

    After breakdown one of the possible mechanisms of occurrence of laser-produced plasma is noted as laser-supported detonation (LSD) wave. This wave consisting of the shock wave and the beam absorbing plasma travels at 1-10 km/s along the beam channel in the direction opposite to the laser incidence. The laser heating structure is recognized as the ZND model of chemical detonation. However, Shimamura et. al, showed that the plasma proceeds the shock wave during LSD regime. The role of shock compression is relatively smaller than preheating by laser. The conventional model is inconsistent with our paper. To investigate the heating structure of a LSD wave, half self-emission half shadowgraph (HSHS) methods provides the self-emission image from the plasma on the top half and the shadowgraph image of the induced shock wave on the bottom half simultaneously. A TEA CO2 laser was used at 10 J incident energy. The locations of both wave fronts were detected from the brightness distribution of the HSHS images. As a result, the propagation of ionization front precedes that of shock wave front by the order of 10-4 m in air and N2. Preheating layer of N2 is shorter than that of air because O2 in air has the lowest ionization energy. Thus, a characteristic of preionization layer depends on the ionization properties because photoionization by the UV radiation generate the seed electrons ahead of shock wave.

  13. Emission Characteristics of a Diesel Engine Operating with In-Cylinder Gasoline and Diesel Fuel Blending

    SciTech Connect

    Prikhodko, Vitaly Y; Curran, Scott; Barone, Teresa L; Lewis Sr, Samuel Arthur; Storey, John Morse; Cho, Kukwon; Wagner, Robert M; Parks, II, James E

    2010-01-01

    Advanced combustion regimes such as homogeneous charge compression ignition (HCCI) and premixed charge compression ignition (PCCI) offer benefits of reduced nitrogen oxides (NOx) and particulate matter (PM) emissions. However, these combustion strategies often generate higher carbon monoxide (CO) and hydrocarbon (HC) emissions. In addition, aldehydes and ketone emissions can increase in these modes. In this study, the engine-out emissions of a compression-ignition engine operating in a fuel reactivity- controlled PCCI combustion mode using in-cylinder blending of gasoline and diesel fuel have been characterized. The work was performed on a 1.9-liter, 4-cylinder diesel engine outfitted with a port fuel injection system to deliver gasoline to the engine. The engine was operated at 2300 rpm and 4.2 bar brake mean effective pressure (BMEP) with the ratio of gasoline to diesel fuel that gave the highest engine efficiency and lowest emissions. Engine-out emissions for aldehydes, ketones and PM were compared with emissions from conventional diesel combustion. Sampling and analysis was carried out following micro-tunnel dilution of the exhaust. Particle geometric mean diameter, number-size distribution, and total number concentration were measured by a scanning mobility particle sizer (SMPS). For the particle mass measurements, samples were collected on Teflon-coated quartz-fiber filters and analyzed gravimetrically. Gaseous aldehydes and ketones were sampled using dinitrophenylhydrazine-coated solid phase extraction cartridges and the extracts were analyzed by liquid chromatography/mass spectrometry (LC/MS). In addition, emissions after a diesel oxidation catalyst (DOC) were also measured to investigate the destruction of CO, HC and formaldehydes by the catalyst.

  14. Spot Fumigation: Fumigant Gas Dispersion and Emission Characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing emissions of volatile organic compounds (VOCs) from fumigant pesticides is mandatory in California, especially in “nonattainment areas” that do not meet federal air quality standards such as in the San Joaquin Valley. A two-year field study was conducted to determine the feasibility of a s...

  15. Effects of grain boundary characteristics of steel on magnetoacoustic emission spectra

    NASA Technical Reports Server (NTRS)

    Namkung, M.; Yost, W. T.; Utrata, D.; Grainger, J. L.; Kushnick, P. W.

    1989-01-01

    Consideration is given to the effects of grain boundary characteristics on the properties of a magnetoacoustic emission spectra obtained by external ac magnetic field-driven domain wall motions. In studies with HY80 steel samples, it is found that the domain wall-defect interaction enhances as more grain boundary is introduced. The enhancement of the domain wall-defect interaction generates high amplitude magnetoacoustic emission pulses and reduces the rate of magnetoacoustic emission events by limiting domain wall motions.

  16. Investigation of the terahertz emission characteristics of MBE-grown GaAs-based nanostructures

    NASA Astrophysics Data System (ADS)

    Takatori, Satoru; Minh, Pham Hong; Estacio, Elmer; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Bailon-Somintac, Michelle; Somintac, Armando; Defensor, Michael; Gabayno, Jacqueline; Awitan, Fritz Christian B.; Jaculbia, Rafael B.; Garcia, Alipio; Ponseca, Carlito, Jr.; Salvador, Arnel; Sarukura, Nobuhiko

    2010-05-01

    We report experimental work on the terahertz emission characteristics of InAs/GaAs quantum dot (QD) structures and GaAs/AlGaAs modulation-doped heterojunctions (MDH's), excited by femtosecond laser. Results showed that the terahertz emission from MDH's can provide information on the GaAs/AlGaAs interface quality while the QD structures have the potential for being intense terahertz emitters; rivaling the emission intensity of p-type bulk InAs.

  17. [Emission Characteristics of VOCs from Typical Restaurants in Beijing].

    PubMed

    Cui, Tong; Cheng, Jing-chen; He, Wan-qing; Ren, Pei-fang; Nie, Lei; Xu, Dong-yao; Pan, Tao

    2015-05-01

    Using the EPA method, emission of volatile organic compounds (VOCs) , sampled from barbecue, Chinese and Western fast-food, Sichuan cuisine and Zhejiang cuisine restaurants in Beijing was investigated. VOCs concentrations and components from different cuisines were studied. The results indicated that based on the calibrated baseline ventilation volume, the VOCs emission level from barbecue was the highest, reaching 12.22 mg · m(-3), while those from fast-food of either Chinese or Western, Sichuan cuisine and Zhejiang cuisine were about 4 mg · m(-3). The components of VOCs from barbecue were different from those in the other cuisines, which were mainly propylene, 1-butene, n-butane, etc. The non-barbecue cuisines consisted of high concentration of alcohols, and Western fast-food contained relatively high proportion of aldehydes and ketones organic compounds. According to emission concentration of baseline ventilation volume, barbecue released more pollutants than the non-barbecue cuisines at the same scale. So, barbecue should be supervised and controlled with the top priority. PMID:26314095

  18. Characteristics of extreme ultraviolet emission from high-Z plasmas

    NASA Astrophysics Data System (ADS)

    Ohashi, H.; Higashiguchi, T.; Suzuki, Y.; Kawasaki, M.; Suzuki, C.; Tomita, K.; Nishikino, M.; Fujioka, S.; Endo, A.; Li, B.; Otsuka, T.; Dunne, P.; O'Sullivan, G.

    2016-03-01

    We demonstrate the extreme ultraviolet (EUV) and soft x-ray sources in the 2 to 7 nm spectral region related to the beyond EUV (BEUV) question at 6.x nm and the water window source based on laser-produced high-Z plasmas. Resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs), extending below the carbon K edge (4.37 nm). An outline of a microscope design for single-shot live cell imaging is proposed based on high-Z plasma UTA source, coupled to multilayer mirror optics.

  19. Radioactivity in gaseous waste discharged from the separations facilities during fourth quarter of 1979

    SciTech Connect

    Sliger, G. J.

    1980-02-22

    This document is issued quarterly for the purpose of summarizing the radioactive gaseous wastes that are discharged from the facilities of the Rockwell Hanford Operations (Rockwell). Data on alpha and beta emissions during 1979 are presented where relevant to the gaseous effluent. Emission data are not included on gaseous wastes produced within the 200 areas by other Hanford contractors.

  20. On-road emission characteristics of CNG-fueled bi-fuel taxis

    NASA Astrophysics Data System (ADS)

    Yao, Zhiliang; Cao, Xinyue; Shen, Xianbao; Zhang, Yingzhi; Wang, Xintong; He, Kebin

    2014-09-01

    To alleviate air pollution and lessen the petroleum demand from the motor vehicle sector in China, natural gas vehicles (NGVs) have been rapidly developed over the last several years. However, the understanding of the real-world emissions of NGVs is very limited. In this study, the emissions from 20 compressed-natural-gas-fueled bi-fuel taxis were measured using a portable emission measurement system (PEMS) under actual driving conditions in Yichang, China. The emission characteristics of the tested vehicles were analyzed, revealing that the average CO2, CO, HC and NOx emissions from the tested compressed-natural-gas (CNG) taxis under urban driving conditions were 1.6, 4.0, 2.0 and 0.98 times those under highway road conditions, respectively. The CO, HC and NOx emissions from Euro 3 CNG vehicles were approximately 40%, 55% and 44% lower than those from Euro 2 vehicles, respectively. Compared with the values for light-duty gasoline vehicles reported in the literature, the CO2 and CO emissions from the tested CNG taxis were clearly lower; however, significant increases in the HC and NOx emissions were observed. Finally, we normalized the emissions under the actual driving cycles of the entire test route to the New European Driving Cycle (NEDC)-based emissions using a VSP modes method developed by North Carolina State University. The simulated NEDC-based CO emissions from the tested CNG taxis were better than the corresponding emissions standards, whereas the simulated NEDC-based HC and NOx emissions greatly exceeded the standards. Thus, more attention should be paid to the emissions from CNG vehicles. As for the CNG-fueled bi-fuel taxis currently in use, the department of environmental protection should strengthen their inspection and supervision to reduce the emissions from these vehicles. The results of this study will be helpful in understanding and controlling emissions from CNG-fueled bi-fuel vehicles in China.

  1. Field emission characteristics of nano-diamond cathode surface by graphitization pretreatment

    NASA Astrophysics Data System (ADS)

    Shi, Yan-mei; Yang, Yan-ning; Liu, Qiao-ping; Li, Wei-xia

    2016-03-01

    Cathode samples of nano-diamond by graphitization pretreatment with different temperatures were fabricated by electrophoresis, then the structures and morphologies of the cathode samples were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), and the field emission tests were conducted. The effects of graphitization pretreatment on the field emission characteristics of nano-diamond cathode surface on titanium substrate are studied. The results indicate that the surface morphologies of nano-diamond cathode samples after graphitization pretreatment change a lot, and the field emission characteristics in low-voltage area are improved obviously. However, in high-voltage area, the curve distortion happens, and it doesn't conform the mechanism of field emission characteristics.

  2. Electron reflection and secondary emission characteristics of sputter-textured pyrolytic graphite surfaces

    NASA Technical Reports Server (NTRS)

    Wintucky, E. G.; Curren, A. N.; Sovey, J. S.

    1981-01-01

    Low secondary and reflected primary electron emission from the collector electrode surfaces is important for optimum collector efficiency and hence for high overall efficiency of microwave amplifier tubes used in communication satellites and in military systems. Ion sputter texturing of the surface effectively suppresses electron emission from pyrolytic graphite, which is a promising collector electrode material. Secondary and reflected primary electron emission characteristics of sputter textured pyrolytic graphite surfaces with microstructures of various sizes and densities are presented. The microstructure with the lowest electron emission levels, less than those of soot, consists of a dense array of tall, thin spires.

  3. Correlation of stress-wave-emission characteristics with fracture aluminum alloys

    NASA Technical Reports Server (NTRS)

    Hartbower, C. E.; Reuter, W. G.; Morais, C. F.; Crimmins, P. P.

    1972-01-01

    A study to correlate stress wave emission characteristics with fracture in welded and unwelded aluminum alloys tested at room and cryogenic temperature is reported. The stress wave emission characteristics investigated were those which serve to presage crack instability; viz., a marked increase in:(1) signal amplitude; (2) signal repetition rate; and (3) the slope of cumulative count plotted versus load. The alloys were 7075-T73, 2219-T87 and 2014-T651, welded with MIG and TIG using 2319 and 4043 filler wire. The testing was done with both unnotched and part-through-crack (PTC) tension specimens and with 18-in.-dia subscale pressure vessels. In the latter testing, a real time, acoustic emission, triangulation system was used to locate the source of each stress wave emission. With such a system, multiple emissions from a given location were correlated with defects found by conventional nondestructive inspection.

  4. [Study on spectral emission characteristics of infrared lamps].

    PubMed

    Wang, J; Chen, Z; Gu, B; Luo, Y; Wang, T

    1999-04-01

    The spectral characteristics at wavelength ranges of 0.35-0.85 microm and 1.72-16.7 microm (5800-600 cm(-1)) for both domestic and imported infrared lamps used in scientific research, industry, medical service, home electrical appliance etc. have heen studied and compared. This paper has provided the theoreical and experimental bases for their applications and improvement in designs, technology of manufacture, quality and performance. PMID:15819000

  5. Associations of individual, household and environmental characteristics with carbon dioxide emissions from motorised passenger travel

    PubMed Central

    Brand, Christian; Goodman, Anna; Rutter, Harry; Song, Yena; Ogilvie, David

    2013-01-01

    Carbon dioxide (CO2) emissions from motorised travel are hypothesised to be associated with individual, household, spatial and other environmental factors. Little robust evidence exists on who contributes most (and least) to travel CO2 and, in particular, the factors influencing commuting, business, shopping and social travel CO2. This paper examines whether and how demographic, socio-economic and other personal and environmental characteristics are associated with land-based passenger transport and associated CO2 emissions. Primary data were collected from 3474 adults using a newly developed survey instrument in the iConnect study in the UK. The participants reported their past-week travel activity and vehicle characteristics from which CO2 emissions were derived using an adapted travel emissions profiling method. Multivariable linear and logistic regression analyses were used to examine what characteristics predicted higher CO2 emissions. CO2 emissions from motorised travel were distributed highly unequally, with the top fifth of participants producing more than two fifth of emissions. Car travel dominated overall CO2 emissions, making up 90% of the total. The strongest independent predictors of CO2 emissions were owning at least one car, being in full-time employment and having a home-work distance of more than 10 km. Income, education and tenure were also strong univariable predictors of CO2 emissions, but seemed to be further back on the causal pathway than having a car. Male gender, late-middle age, living in a rural area and having access to a bicycle also showed significant but weaker associations with emissions production. The findings may help inform the development of climate change mitigation policies for the transport sector. Targeting individuals and households with high car ownership, focussing on providing viable alternatives to commuting by car, and supporting planning and other policies that reduce commuting distances may provide an equitable and

  6. L X-ray emission from fast highly charged Cu ions in collisions with gaseous targets: Saturation effect in excitation and transfer

    NASA Astrophysics Data System (ADS)

    Kumar, Ajay; Misra, D.; Kadhane, U.; Kelkar, A. H.; Dhal, B. B.; Tribedi, L. C.

    2006-11-01

    We have measured L X-ray production cross sections for highly charged 156 MeV Be-like Cu ions in collisions with gaseous targets of H 2, Ne, Ar, Kr and Xe. In the present collision systems, measured projectile L X-ray intensity is contributed by the excitation as well as electron transfer processes. The projectile L X-ray production cross sections are found to increase initially and then saturate with increasing target atomic number. The charge state dependence of projectile L X-ray production cross sections have been measured with Kr target.

  7. Evaluation of Gas, Oil and Wood Pellet Fueled Residential Heating System Emissions Characteristics

    SciTech Connect

    McDonald, R.

    2009-12-01

    This study has measured the emissions from a wide range of heating equipment burning different fuels including several liquid fuel options, utility supplied natural gas and wood pellet resources. The major effort was placed on generating a database for the mass emission rate of fine particulates (PM 2.5) for the various fuel types studied. The fine particulates or PM 2.5 (less than 2.5 microns in size) were measured using a dilution tunnel technique following the method described in US EPA CTM-039. The PM 2.5 emission results are expressed in several units for the benefit of scientists, engineers and administrators. The measurements of gaseous emissions of O{sub 2}, CO{sub 2}, CO, NO{sub x} and SO{sub 2} were made using a combustion analyzer based on electrochemical cells These measurements are presented for each of the residential heating systems tested. This analyzer also provides a steady state efficiency based on stack gas and temperature measurements and these values are included in the report. The gaseous results are within the ranges expected from prior emission studies with the enhancement of expanding these measurements to fuels not available to earlier researchers. Based on measured excess air levels and ultimate analysis of the fuel's chemical composition the gaseous emission results are as expected and fall within the range provided for emission factors contained in the US-EPA AP 42, Emission Factors Volume I, Fifth Edition. Since there were no unexpected findings in these gaseous measurements, the bulk of the report is centered on the emissions of fine particulates, or PM 2.5. The fine particulate (PM 2.5) results for the liquid fuel fired heating systems indicate a very strong linear relationship between the fine particulate emissions and the sulfur content of the liquid fuels being studied. This is illustrated by the plot contained in the first figure on the next page which clearly illustrates the linear relationship between the measured mass of fine

  8. In-plane resolution characteristics for a positron emission tomograph

    SciTech Connect

    Yamamoto, S.; Amano, M.; Hirose, Y.; Ida, H.; Miura, S.; Kanno, I.

    1989-02-01

    HEADTOME IV is a PET which consists of 96 detector units per ring. Each detector unit consists of eight 3mm wide bismuth germanate (BGO) crystals, a pair of light guides and a dual module photomultiplier tube (PMT), and uses pulse hight ratio logic to determine the crystal of interaction. In-plane resolution of 4.5 mm full-width at half-maximum (FWHM) was obtained without any sampling motion such as wobble. The in-plane resolution of a PET which used discrete detector arrangement with sampling motion was determined by intrinsic crystal pair resolution. However the in-plane resolution without sampling motion is determined by detector center-to-center spacing because of incomplete linear sampling, and contain nonuniformity due to aliasing artifacts. In the case of the HEADTOME IV, the in-plane resolution is determined by not only the factors mentioned above (i.e. crystal pair resolution and center-to-center spacing) but also statistical fluctuations in calculating the position because the light output of BGO is not enough to perfectly separate each BGO. With these special configurations, the in-plane resolution of the HEADTOME IV may show different characteristics from those of the PET with discrete detector arrangement. In this paper, the authors investigated three in-plane resolution characteristics of the HEADTOME IV, i.e. resolution with distance from the center, variation of the in-plane resolution, effect of imbalance of gain.

  9. Secondary electron emission characteristics of oxide electrodes in flat electron emission lamp

    NASA Astrophysics Data System (ADS)

    Chiang, Chang-Lin; Zeng, Hui-Kai; Li, Chia-Hung; Li, Jung-Yu; Chen, Shih-Pu; Lin, Yi-Ping; Hsieh, Tai-Chiung; Juang, Jenh-Yih

    2016-01-01

    The present study concerns with the secondary electron emission coefficient, γ, of the cathode materials used in the newly developed flat electron emission lamp (FEEL) devices, which essentially integrates the concept of using cathode for fluorescent lamp and anode for cathode ray tube (CRT) to obtain uniform planar lighting. Three different cathode materials, namely fluorine-doped tin oxide (FTO), aluminum oxide coated FTO (Al2O3/FTO) and magnesium oxide coated FTO (MgO/FTO) were prepared to investigate how the variations of γ and working gases influence the performance of FEEL devices, especially in lowering the breakdown voltage and pressure of the working gases. The results indicate that the MgO/FTO bilayer cathode exhibited a relatively larger effective secondary electron emission coefficient, resulting in significant reduction of breakdown voltage to about 3kV and allowing the device to be operated at the lower pressure to generate the higher lighting efficiency.

  10. Gaseous dielectrics V

    SciTech Connect

    Christophorou, L.G.; Bouldin, D.W.

    1987-01-01

    This symposium represents a transdisciplinary and comprehensive approach to the study of gaseous dielectrics. The goal of the symposium was to demonstrate the effective coupling between basic and applied research and modern technology achieved in this area, and to guide future research and development and industrial use of gaseous dielectrics. Separate abstracts were prepared for 85 papers in these proceedings. (DWL)

  11. Secondary electron emission characteristics of ion-textured copper and high-purity isotropic graphite surfaces

    NASA Technical Reports Server (NTRS)

    Curren, A. N.; Jensen, K. A.

    1984-01-01

    Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for untreated and ion textured oxygen free high conductivity copper and untreated and ion textured high purity isotropic graphite surfaces are presented for a range of primary electron beam energies and beam impingement angles. This investigation was conducted to provide information that would improve the efficiency of multistage depressed collectors (MDC's) for microwave amplifier traveling wave tubes in space communications and aircraft applications. For high efficiency, MDC electrode surfaces must have low secondary electron emission characteristics. Although copper is a commonly used material for MDC electrodes, it exhibits relatively high levels of secondary electron emission if its surface is not treated for emission control. Recent studies demonstrated that high purity isotropic graphite is a promising material for MDC electrodes, particularly with ion textured surfaces. The materials were tested at primary electron beam energies of 200 to 2000 eV and at direct (0 deg) to near grazing (85 deg) beam impingement angles. True secondary electron emission and relative reflected primary electron yield characteristics of the ion textured surfaces were compared with each other and with those of untreated surfaces of the same materials. Both the untreated and ion textured graphite surfaces and the ion treated copper surface exhibited sharply reduced secondary electron emission characteristics relative to those of untreated copper. The ion treated graphite surface yielded the lowest emission levels.

  12. Secondary electron emission characteristics of untreated and ion-textured titanium

    NASA Technical Reports Server (NTRS)

    Curren, Arthur N.; Jensen, Kenneth A.; Blackford, Gary A.

    1989-01-01

    Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield are presented for untreated (simply machined) and ion-textured, high-purity titanium over ranges of primary electron beam energies and beam impingement angles. The purpose of the investigation was to explore the feasibility of using titanium as electrode material in the multistage depressed collectors (MDC's) used in microwave amplifier traveling wave tubes (TWT's) for space communications and aircraft applications. Because of its relatively low density and thermal expansion characteristics and relatively high strength, thermal emissivity, and melting temperature, titanium presents itself as a possible candidate for the MDC electrode application. A detailed description of the method of ion texturing the titanium is included. Although the ion-treated surface considered in this study is not presented as being optimum from the standpoint of secondary electron emission suppression, it nevertheless serves to demonstrate that the surface can be modified by this procedure to significantly reduce these emission characteristics relative to those of the untreated surface. Further studies can reasonably be expected to produce surfaces with even lower secondary emission characteristics. The titanium surface were tested at primary electron beam energies of 200 to 2000 eV and at direct (0 deg) to near-grazing (85 deg) beam impingement angles. True secondary electron emission and relative reflected primary electron yield characteristics of the surfaces were compared with each other and with textured titanium surface exhibited secondary electron emission characteristics sharply lower than those exhibited by untreated titanium or copper. Clearly, then, in consideration of the secondary electron emission suppression of ion-textured titanium along with its other favorable physical properties, it must be included as a potential candidate for use as MDC electrode

  13. [Emission Characteristics of Vehicle Exhaust in Beijing Based on Actual Traffic Flow Information].

    PubMed

    Fan, Shou-bin; Tian, Ling-di; Zhang, Dong-xu; Qu, Song

    2015-08-01

    The basic data of traffic volume, vehicle type constitute and speed on road networks in Beijing was obtained fly modei simulation and field survey. Based on actual traffic flow information and. emission factors data with temporal and spatial distribution features, emission inventory of motor vehicle exhaust in Beijing was built on the ArcGIS platform, meanwhile, the actual road emission characteristics and spatial distribution of the pollutant emissions were analyzed. The results showed that the proportion of passenger car was higher than 89% on each type of road in the urban, and the proportion of passenger car was the highest in suburban roads as well while the pickup truck, medium truck, heavy truck, motorbus, tractor and motorcycle also occupied a certain proportion. There was a positive correlation between the pollutant emission intensity and traffic volume, and the emission intensity was generally higher in daytime than nighttime, but the diurnal variation trend of PM emission was not clear for suburban roads and the emission intensity was higher in nighttime than daytime for highway. The emission intensities in urban area, south, southeast and northeast areas near urban were higher than those in the western and northern mountainous areas with lower density of road network. The ring roads in urban and highways in suburban had higher emission intensity because of the heavy traffic volume. PMID:26592000

  14. [Study of the microwave emissivity characteristics over different land cover types].

    PubMed

    Zhang, Yong-Pan; Jiang, Ling-Mei; Qiu, Yu-Bao; Wu, Sheng-Li; Shi, Jian-Cheng; Zhang, Li-Xin

    2010-06-01

    The microwave emissivity over land is very important for describing the characteristics of the lands, and it is also a key factor for retrieving the parameters of land and atmosphere. Different land covers have their emission behavior as a function of structure, water content, and surface roughness. In the present study the global land surface emissivities were calculated using six month (June, 2003-August, 2003, Dec, 2003-Feb, 2004) AMSR-E L2A brightness temperature, MODIS land surface temperature and the layered atmosphere temperature, and humidity and pressure profiles data retrieved from MODIS/Aqua under clear sky conditions. With the information of IGBP land cover types, "pure" pixels were used, which are defined when the fraction cover of each land type is larger than 85%. Then, the emissivity of sixteen land covers at different frequencies, polarization and their seasonal variation were analyzed respectively. The results show that the emissivity of vegetation including forests, grasslands and croplands is higher than that over bare soil, and the polarization difference of vegetation is smaller than that of bare soil. In summer, the emissivity of vegetation is relatively stable because it is in bloom, therefore the authors can use it as its emissivity in our microwave emissivity database over different land cover types. Furthermore, snow cover can heavily impact the change in land cover emissivity, especially in winter. PMID:20707126

  15. 40 CFR 90.415 - Raw gaseous sampling procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Raw gaseous sampling procedures. 90.415 Section 90.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous...

  16. 40 CFR 91.415 - Raw gaseous sampling procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Raw gaseous sampling procedures. 91.415 Section 91.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures §...

  17. Field measurement and estimate of gaseous and particle pollutant emissions from cooking and space heating processes in rural households, northern China

    NASA Astrophysics Data System (ADS)

    Chen, Yuanchen; Shen, Guofeng; Liu, Weijian; Du, Wei; Su, Shu; Duan, Yonghong; Lin, Nan; Zhuo, Shaojie; Wang, Xilong; Xing, Baoshan; Tao, Shu

    2016-01-01

    Pollutant emissions into outdoor air from cooking and space heating processes with various solid fuels were measured, and daily household emissions were estimated from the kitchen performance tests. The burning of honeycomb briquette had the lowest emission factors, while the use of wood produced the highest pollutants. Daily emissions from space heating were significantly higher than those from cooking, and the use of honeycomb briquette for cooking and raw coal chunk for space heating reduces 28%, 24% and 25% for CO, PM10 and PM2.5, compared to wood for cooking and peat for space heating. Much higher emissions were observed during the initial phase than the stable phase due to insufficient air supply and lower combustion temperature at the beginning of burning processes. However, more mass percent of fine particles formed in the later high temperature stable burning phase may increase potential inhalation exposure risks.

  18. Estimation of local fleet characteristics data for improved emission inventory development

    SciTech Connect

    Heiken, J.; Pollack, A.; Austin, B.

    1996-12-31

    Considerable effort in recent years has been focused on the improvement of on-road mobile source emission factors with much less attention paid to the refinement of activity and fleet characteristics estimates. Current emissions modeling practices commonly use emission factor model defaults or statewide averages for fleet and activity data. As part of the US EPA`s Emission Inventory Improvement Program (EIIP), ENVIRON developed methodologies to derive locality-specific fleet characteristics data from existing data sources in order to improve local emission inventory estimates. Data sources examined included remote sensing studies and inspection and maintenance (I/M) program data. In this paper, we focus on two specific examples: (1) the calculation of mileage accumulation rates from Arizona I/M program data, and (2) the calculation of registration distribution from a Sacramento remote sensing database. In both examples, differences exist between the calculated distributions and those currently used for air quality modeling, resulting in significant impacts on the estimated mobile source emissions inventory. For example, use of the automobile registration distribution data derived from the Sacramento Pilot I/M Program remote sensing database results in an increase in estimated automobile TOG, CO and NO{sub x} of 15, 24 and 17 percent, respectively, when used in place of the default registration distribution in the current California Air Resources Board MVEI7G emissions model.

  19. Methane emission from natural wetlands: Global distribution, area, and environmental characteristics of sources

    SciTech Connect

    Matthews, E.; Fung, I. )

    1987-03-01

    A global data base of wetlands at 1 degree resolution was developed from the integration of three independent global, digital sources: (1) vegetation, (2) soil properties and (3) fractional inundation in each 1 degree cell. The integration yielded a global distribution of wetland sites identified with in situ ecological and environmental characteristics. The wetland sites were classified into five major groups on the basis of environmental characteristics governing methane emissions. The global wetland area derived in this study is 5.3 trillion sq m, approximately twice the wetland area previously used in methane emission studies. Methane emission was calculated using methane fluxes for the major wetland groups, and simple assumptions about the duration of the methane production season. The annual methane emission from wetlands is about 110 Tg, well within the range of previous estimates. Tropical/subtropical peat-poor swamps from 20 degrees N to 30 degrees S account from 30% of the global wetland area and 25% of the total methane emission. About 60% of the total emission comes from peat-rich bogs concentrated from 50-70 degrees N, suggesting that the highly seasonal emission from these ecosystems is the major contributor to the large annual oscillations observed in atmospheric methane concentrations at these latitudes. 78 refs., 6 figs., 5 tabs.

  20. Characteristics of NOx emission from Chinese coal-fired power plants equipped with new technologies

    NASA Astrophysics Data System (ADS)

    Ma, Zizhen; Deng, Jianguo; Li, Zhen; Li, Qing; Zhao, Ping; Wang, Liguo; Sun, Yezhu; Zheng, Hongxian; Pan, Li; Zhao, Shun; Jiang, Jingkun; Wang, Shuxiao; Duan, Lei

    2016-04-01

    Coal combustion in coal-fired power plants is one of the important anthropogenic NOx sources, especially in China. Many policies and methods aiming at reducing pollutants, such as increasing installed capacity and installing air pollution control devices (APCDs), especially selective catalytic reduction (SCR) units, could alter NOx emission characteristics (NOx concentration, NO2/NOx ratio, and NOx emission factor). This study reported the NOx characteristics of eight new coal-fired power-generating units with different boiler patterns, installed capacities, operating loads, and coal types. The results showed that larger units produced less NOx, and anthracite combustion generated more NOx than bitumite and lignite combustion. During formation, the NOx emission factors varied from 1.81 to 6.14 g/kg, much lower than those of older units at similar scales. This implies that NOx emissions of current and future units could be overestimated if they are based on outdated emission factors. In addition, APCDs, especially SCR, greatly decreased NOx emissions, but increased NO2/NOx ratios. Regardless, the NO2/NOx ratios were lower than 5%, in accordance with the guidelines and supporting the current method for calculating NOx emissions from coal-fired power plants that ignore NO2.

  1. On-road pollutant emission and fuel consumption characteristics of buses in Beijing.

    PubMed

    Wang, Aijuan; Ge, Yunshan; Tan, Jianwei; Fu, Mingliang; Shah, Asad Naeem; Ding, Yan; Zhao, Hong; Liang, Bin

    2011-01-01

    On-road emission and fuel consumption (FC) levels for Euro III and IV buses fueled on diesel and compressed natural gas (CNG) were compared, and emission and FC characteristics of buses were analyzed based on approximately 28,700 groups of instantaneous data obtained in Beijing using a portable emissions measurement system (PEMS). The experimental results revealed that NOx and PM emissions from CNG buses were decreased by 72.0% and 82.3% respectively, compared with Euro IV diesel buses. Similarly, these emissions were reduced by 75.2% and 96.3% respectively, compared with Euro III diesel buses. In addition, CO2, CO, HC, NOx, PM emissions and FC of Euro IV diesel buses were reduced by 26.4%, 75.2%, 73.6%, 11.4%, 79.1%, and 26.0%, respectively, relative to Euro III diesel buses. The CO2, CO, HC, NOx, PM emissions and FC factors all decreased with bus speed increased, while increased as bus acceleration increased. At the same time, the emission/FC rates as well as the emission/FC factors exhibited a strong positive correlation with the vehicle specific power (VSP). They all were the lowest when VSP < 0, and then rapidly increased as VSP increased. Furthermore, both the emission/FC rates and emission/FC factors were the highest at accelerations, higher at cruise speeds, and the lowest at decelerations for non-idling buses. These results can provide a base reference to further estimate bus emission and FC inventories in Beijing. PMID:21520811

  2. Gaseous and Particulate Emissions from Diesel Engines at Idle and under Load: Comparison of Biodiesel Blend and Ultralow Sulfur Diesel Fuels

    PubMed Central

    Chin, Jo-Yu; Batterman, Stuart A.; Northrop, William F.; Bohac, Stanislav V.; Assanis, Dennis N.

    2015-01-01

    Diesel exhaust emissions have been reported for a number of engine operating strategies, after-treatment technologies, and fuels. However, information is limited regarding emissions of many pollutants during idling and when biodiesel fuels are used. This study investigates regulated and unregulated emissions from both light-duty passenger car (1.7 L) and medium-duty (6.4 L) diesel engines at idle and load and compares a biodiesel blend (B20) to conventional ultralow sulfur diesel (ULSD) fuel. Exhaust aftertreatment devices included a diesel oxidation catalyst (DOC) and a diesel particle filter (DPF). For the 1.7 L engine under load without a DOC, B20 reduced brake-specific emissions of particulate matter (PM), elemental carbon (EC), nonmethane hydrocarbons (NMHCs), and most volatile organic compounds (VOCs) compared to ULSD; however, formaldehyde brake-specific emissions increased. With a DOC and high load, B20 increased brake-specific emissions of NMHC, nitrogen oxides (NOx), formaldehyde, naphthalene, and several other VOCs. For the 6.4 L engine under load, B20 reduced brake-specific emissions of PM2.5, EC, formaldehyde, and most VOCs; however, NOx brake-specific emissions increased. When idling, the effects of fuel type were different: B20 increased NMHC, PM2.5, EC, formaldehyde, benzene, and other VOC emission rates from both engines, and changes were sometimes large, e.g., PM2.5 increased by 60% for the 6.4 L/2004 calibration engine, and benzene by 40% for the 1.7 L engine with the DOC, possibly reflecting incomplete combustion and unburned fuel. Diesel exhaust emissions depended on the fuel type and engine load (idle versus loaded). The higher emissions found when using B20 are especially important given the recent attention to exposures from idling vehicles and the health significance of PM2.5. The emission profiles demonstrate the effects of fuel type, engine calibration, and emission control system, and they can be used as source profiles for apportionment

  3. THE LIQUID AND GASEOUS FUEL DISTRIBUTION SYSTEM

    EPA Science Inventory

    The report describes the national liquid and gaseous fuel distribution system. he study leading to the report was performed as part of an effort to better understand emissions of volatile organic compounds from the fuel distribution system. he primary, secondary, and tertiary seg...

  4. LIQUID AND GASEOUS FUEL DISTRIBUTION SYSTEM

    EPA Science Inventory

    The report describes the national liquid and gaseous fuel distribution system. he study leading to the report was performed as part of an effort to better understand emissions of volatile organic compounds from the fuel distribution system. he primary, secondary, and tertiary seg...

  5. Solid and Gaseous Fuels.

    ERIC Educational Resources Information Center

    Schultz, Hyman; And Others

    1989-01-01

    This review covers methods of sampling, analyzing, and testing coal, coke, and coal-derived solids and methods for the chemical, physical, and instrumental analyses of gaseous fuels. The review covers from October 1986, to September 1988. (MVL)

  6. The influence of oxidation properties on the electron emission characteristics of porous silicon

    NASA Astrophysics Data System (ADS)

    He, Li; Zhang, Xiaoning; Wang, Wenjiang; Wei, Haicheng

    2016-09-01

    In order to investigate the influence of oxidation properties such as oxygen content and its distribution gradient on the electron emission characteristics of porous silicon (PS) emitters, emitters with PS thickness of 8 μm, 5 μm, and 3 μm were prepared and then oxidized by electrochemical oxidation (ECO) and ECO-RTO (rapid thermal oxidation) to get different oxidation properties. The experimental results indicated that the emission current density, efficiency, and stability of the PS emitters are mainly determined by oxidation properties. The higher oxygen content and the smaller oxygen distribution gradient in the PS layer, the larger emission current density and efficiency we noted. The most favorable results occurred for the PS emitter with the smallest oxygen distribution gradient and the highest level of oxygen content, with an emission current density of 212.25 μA/cm2 and efficiency of 59.21‰. Additionally, it also demonstrates that thick PS layer benefits to the emission stability due to its longer electron acceleration tunnel. The FN fitting plots indicated that the effective emission areas of PS emitters can be enlarged and electron emission thresholds is decreased because of the higher oxygen content and smaller distribution gradient, which were approved by the optical micrographs of top electrode of PS emitters before and after electron emission.

  7. Influence of high energy ion irradiation on the field emission characteristics of CVD diamond films

    NASA Astrophysics Data System (ADS)

    Koinkar, P. M.; Khairnar, R. S.; Khan, S. A.; Gupta, R. P.; Avasthi, D. K.; More, M. A.

    2006-03-01

    The field emission characteristics of ion-irradiated CVD diamond thin film deposited on silicon substrate has been studied. The diamond thin films, synthesized by hot filament chemical vapor deposition (HFCVD) method, were irradiated by high energy (100 MeV) silver ion (107Ag+ with charge state 9) in the fluence range of 3 × 1011-1 × 1013 ions/cm2. The CVD diamond films were characterized by Raman spectroscopy. The Raman spectra of irradiated samples clearly reveal structural damage due to ion irradiation, which is observed to be fluence dependent. However complete graphitization is not observed. The field emission current-voltage (I-V) characteristics were recorded in 'diode' configuration at base pressure ∼1 × 10-8 mbar. Upon ion irradiation the field emission current is observed to increase with the reduction in the threshold voltage, required to draw 1 μA current. The results indicate that ion irradiation leads to better emission characteristics and the structural damage caused by ion irradiation plays a significant role in emission behavior of CVD diamond films.

  8. The determination of cloud masses and dust characteristics from submillimetre thermal emission

    NASA Technical Reports Server (NTRS)

    Hildebrand, R. H.

    1983-01-01

    The principles by which the dust and masses and total masses of interstellar clouds and certain characteristics of interstellar dust grains can be derived from observations of far infrared and submillimeter thermal emission are reviewed. To the extent possible, the discussion will be independent of particular grain models.

  9. Emission characteristics of dispenser cathodes with a fine-grained tungsten top layer

    NASA Astrophysics Data System (ADS)

    Kimura, S.; Higuchi, T.; Ouchi, Y.; Uda, E.; Nakamura, O.; Sudo, T.; Koyama, K.

    1997-02-01

    In order to improve the emission stability of the Ir-coated dispenser cathode under ion bombardment, a fine-grained tungsten top layer was applied on the substrate porous tungsten plug before Ir coating. The emission characteristics were studied after being assembled in a CRT gun. Cathode current was measured under pulse operation in a range of 0.1-9% duty. Remarkable anti-ion bombardment characteristics were observed over the range of 1-6% duty. The improved cathode showed 1.5 times higher emission current than that of a conventional Ir-coated dispenser cathode at 4% duty. AES analysis showed that the recovering rates of surface Ba and O atoms after ion bombardment were 2.5 times higher. From these results it is confirmed that the Ir coated cathode with a fine-grained tungsten top layer is provided with a good tolerance against the ion bombardment.

  10. Characteristics of optical emission intensities and bubblelike phenomena induced by laser ablation in supercritical fluids

    NASA Astrophysics Data System (ADS)

    Takada, Noriharu; Machmudah, Siti; Goto, Hiroshi; Wahyudiono; Goto, Motonobu; Sasaki, Koichi

    2014-01-01

    We investigated the characteristics of laser ablation phenomena in supercritical fluids by optical emission and shadowgraph imaging. In comparison with laser ablation in liquid H2O, the optical emission of a laser ablation plasma produced in supercritical H2O had a longer lifetime and a larger transport length. It was found in supercritical CO2 that laser ablation plasmas with bright optical emissions were produced at a mass density of approximately 300 kg/m3. A clear correlation between the optical emission intensity and the density fluctuation was not observed in our experimental results, which were obtained in a regime deviated from the critical point. Bubblelike hollows were observed by shadowgraph imaging in both supercritical H2O and CO2. The dynamics of the bubblelike hollows were different from the dynamics of a cavitation bubble induced by laser ablation in a liquid medium but relatively similar to the dynamics of ambient gas in gas-phase laser ablation.

  11. Characteristics of Zero-Emission Activities in the Grain Cleaning and Flour Milling Industry

    NASA Astrophysics Data System (ADS)

    Zhang, Shifeng; Yamamoto, Kayoko; Izumi, Jun

    The aim of this study is to clarify the characteristics of zero-emission activities in the grain cleaning and flour milling industry. The findings of this study are summarized in the following two points: (1) There are very few common features among factories in regards to zero-emission efforts. High processing cost, lack of manpower, recycling traders and space for wastes classification are pointed out as difficulties, and information gathering from the outside of each company is not widespread. (2) Zero-emission activities differ according to factory, and the number of recycling categories is less than the number of waste categories, even though wheat is the only raw material. Ten different kinds of waste were identified, and the lack of means to recycle this waste was identified as a significant hindrance to zero emissions.

  12. Evaluating the Effects of Aromatics Content in Gasoline on Gaseous and Particulate Matter Emissions from SI-PFI and SIDI Vehicles.

    PubMed

    Karavalakis, Georgios; Short, Daniel; Vu, Diep; Russell, Robert; Hajbabaei, Maryam; Asa-Awuku, Akua; Durbin, Thomas D

    2015-06-01

    We assessed the emissions response of a fleet of seven light-duty gasoline vehicles for gasoline fuel aromatic content while operating over the LA92 driving cycle. The test fleet consisted of model year 2012 vehicles equipped with spark-ignition (SI) and either port fuel injection (PFI) or direct injection (DI) technology. Three gasoline fuels were blended to meet a range of total aromatics targets (15%, 25%, and 35% by volume) while holding other fuel properties relatively constant within specified ranges, and a fourth fuel was formulated to meet a 35% by volume total aromatics target but with a higher octane number. Our results showed statistically significant increases in carbon monoxide, nonmethane hydrocarbon, particulate matter (PM) mass, particle number, and black carbon emissions with increasing aromatics content for all seven vehicles tested. Only one vehicle showed a statistically significant increase in total hydrocarbon emissions. The monoaromatic hydrocarbon species that were evaluated showed increases with increasing aromatic content in the fuel. Changes in fuel composition had no statistically significant effect on the emissions of nitrogen oxides (NOx), formaldehyde, or acetaldehyde. A good correlation was also found between the PM index and PM mass and number emissions for all vehicle/fuel combinations with the total aromatics group being a significant contributor to the total PM index followed by naphthalenes and indenes. PMID:25938171

  13. [Marine Emission Inventory and Its Temporal and Spatial Characteristics in the City of Shenzhen].

    PubMed

    Yang, Jing; Yin, Pei-ling; Ye, Si-qi; Wang, Shui-sheng; Zheng, Jun-yu; Ou, Jia-min

    2015-04-01

    To analyze the characteristic of marine emission in Shenzhen City, activity-based and fuel-based approaches were utilized to develop the marine emission inventory for the year of 2010, using the vessel files from the Lloyd's register of shipping (LR) and vessel track data from the automatic identification system (AIS). The marine emission inventory was temporally (resolution: 1 hour) and spatially (resolution: 1 km x 1 km) allocated based on the vessel track data. Results showed that total emissions of SO2, NO(x), CO, PM10, PM2.5 and VOCs from marine vessels in Shenzhen City were about 13.6 x 10(3), 23.3 x 10(3), 2.2 x 10(3), 1.9 x 10(3), 1.7 x 10(3) and 1. x 10(3) t, respectively. Among various types of marine vessels, emission from container vessels was the highest; for different driving modes, hotelling mode was found with the largest mission. Marine emissions were generally higher in the daytime, with vessel-specific peaks. For spatial distributions, in general, marine emissions were zonally distributed with hot spots in the western port group, Dapeng Bay and the key waterway. PMID:26164893

  14. Emission characteristics of particulate matter and heavy metals from small incinerators and boilers

    NASA Astrophysics Data System (ADS)

    Yoo, Jong-Ik; Kim, Ki-Heon; Jang, Ha-Na; Seo, Yong-Chil; Seok, Kwang-Seol; Hong, Ji-Hyung; Jang, Min

    The characteristics of particulate matter (PM) emission such as the estimation of emission factors, size distributions and of heavy metal emission from small-size incinerators and boilers have been investigated. In PM-10 emission, a fine mode was found in the formation of sub-micron PM by growth of nucleated aerosol of metal vapor, having a bimodal particle size distribution in overall size range. The emission ratios of PM-10 to TPM (total PM) from boilers and incinerators ranged from 29% to 62% and 10% to 84%, respectively, which resulted in more and larger sized PM emission due to poorer combustion from solid waste incinerators than boilers. The targeted metals were copper, cadmium, manganese, chromium, magnesium, lead, zinc and copper, and their contents in bottom ash, fly ash and dust (PM) were compared. More volatile metals such as cadmium, lead and zinc showed higher enrichment in PM emitted through stack than bottom ashes. Cadmium, copper, lead and zinc on the fine PM under 2.5 μm accounted for approximately 90% of the total mass of each metal in PM-10. The effects of chlorine concentration and temperature on such metals emission were also observed due to their volatility changes.

  15. Emission Characteristics of A P and W Axially Staged Sector Combustor

    NASA Technical Reports Server (NTRS)

    He, Zhuohui J.; Wey, Changlie; Chang, Clarence T.; Lee, Chi Ming; Surgenor, Angela D.; Kopp-Vaughan, Kristin; Cheung, Albert

    2016-01-01

    Emission characteristics of a three-cup P and W Axially Controlled Stoichiometry (ACS) sector combustor are reported in this article. Multiple injection points and fuel staging strategies are used in this combustor design. Pilot-stage injectors are located on the front dome plate of the combustor, and main-stage injectors are positioned on the top and bottom of the combustor liners downstream. Low power configuration uses only pilot-stage injectors. Main-stage injectors are added to high power configuration to help distribute fuel more evenly and achieve overall lean burn yielding very low NOx emissions. Combustion efficiencies at four ICAO LTO conditions were all above 99%. Three EINOx emissions correlation equations were developed based on the experimental data to describe the NOx emission trends of this combustor concept. For the 7% and 30% engine power conditions, NOx emissions are obtained with the low power configuration, and the EINOx values are 6.16 and 6.81. The high power configuration was used to assess 85% and 100% engine power NOx emissions, with measured EINOx values of 4.58 and 7.45, respectively. The overall landing-takeoff cycle NOx emissions are about 12% relative to ICAO CAEP/6 level.

  16. [Particle emission characteristics of diesel bus fueled with bio-diesel].

    PubMed

    Lou, Di-Ming; Chen, Feng; Hu, Zhi-Yuan; Tan, Pi-Qiang; Hu, Wei

    2013-10-01

    With the use of the Engine Exhaust Particle Sizer (EEPS), a study on the characteristics of particle emissions was carried out on a China-IV diesel bus fueled with blends of 5% , 10% , 20% , 50% bio-diesel transformed from restaurant waste oil and China-IV diesel (marked separately by BD5, BD10, BD20, BD50), pure bio-diesel (BD100) and pure diesel (BD0). The results indicated that particulate number (PN) and mass (PM) emissions of bio-diesel blends increased with the increase in bus speed and acceleration; with increasing bio-diesel content, particulate emissions displayed a relevant declining trend. In different speed ranges, the size distribution of particulate number emissions (PNSD) was bimodal; in different acceleration ranges, PNSD showed a gradual transition from bimodal shape to unimodal when bus operation was switched from decelerating to accelerating status. Bio-diesel blends with higher mixture ratios showed significant reduction in PN emissions for accumulated modes, and the particulate number emission peaks moved towards smaller sizes; but little change was obtained in PN emissions for nuclei modes; reduction also occurred in particle geometric diameter (Dg). PMID:24364288

  17. Anthropogenic emissions during Arctas-A: mean transport characteristics and regional case studies

    NASA Astrophysics Data System (ADS)

    Harrigan, D. L.; Fuelberg, H. E.; Simpson, I. J.; Blake, D. R.; Carmichael, G. R.; Diskin, G. S.

    2011-08-01

    The National Aeronautics and Space Administration (NASA) conducted the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission during 2008 as a part of the International Polar Year (IPY). The purpose of ARCTAS was to study the factors responsible for changes in the Arctic's atmospheric composition and climate. A major emphasis was to investigate Arctic haze, which is most pronounced during winter and early spring. This study focuses on the spring phase of ARCTAS (ARCTAS-A) that was based in Alaska during April 2008. Although anthropogenic emissions historically have been associated with Arctic haze, biomass burning emissions dominated the ARCTAS-A period and have been the focus of many ARCTAS related studies. This study determines mean transport characteristics of anthropogenic emissions during ARCTAS-A. Trajectories are initiated each day from three significant regions of anthropogenic emissions (Asia, North America, and Europe). The fifteen day forward trajectories are calculated using data from the Weather Research and Forecasting (WRF) model at 45 km horizontal resolution. The trajectory calculations indicate: origins of emissions that reach the Arctic (defined as north of 70° N) within fifteen days, pathways of these emissions, Arctic entry locations, and altitudes at which the trajectories enter the Arctic. Three cases during the ARCTAS-A period (one for each of the regions above) are examined using backward trajectories and chemical fingerprinting based on in situ data sampled from the NASA DC-8. The fingerprinting utilizes volatile organic compounds that represent pure anthropogenic tracers, Asian anthropogenic pollution, incomplete combustion, and natural gas emissions. We determine flight legs containing anthropogenic emissions and the pathways travelled by these emissions. Results show that the DC-8 sampled anthropogenic emissions from Asia, North America, and Europe during the spring phase of ARCTAS. The

  18. Field emission characteristics of electrochemically synthesized nickel nanowires with oxygen plasma post-treatment.

    PubMed

    Joo, Jinsoo; Lee, Sun Jeong; Park, Dong Hyuk; Kim, Young Soo; Lee, Yeonhee; Lee, Cheol Jin; Lee, Seong-Rae

    2006-07-28

    The field emissive, electrical, magnetic, and structural characteristics of nickel (Ni) nanowires synthesized using the electrochemical deposition method with an alumina nanoporous template are reported. The synthesis and formation of Ni nanowires were confirmed by XRD, SEM, and HR-TEM experiments. Ferromagnetic hysteresis curves and the metallic temperature dependence of the current-voltage characteristics were observed for the Ni nanowire systems. The nanotip emitters of the field emission cells of the Ni nanowires after O(2) plasma treatment were easily patterned using the solution drop casting (SDC) method, in which the Ni nanowires were homogeneously dispersed in organic solvents, and then dropped and dried on an n-type doped Si substrate as the cathode. For the O(2) plasma treated Ni nanowires, we observed that the inhomogeneous oxidized layer on their surface was reduced, that the current density of the field emission cell increased from approximately 3.0 x 10(-9) to approximately 1.0 x 10(-3) A cm(-2) due to field emission, and that the lowest threshold electric field was approximately 4 V microm(-1). The field enhancement factor was estimated as approximately 1300 for the O(2) plasma treated Ni nanowires. The evolution of the field emission obtained from the phosphor screen was observed at different applied electric fields. PMID:19661596

  19. Textured carbon on copper: A novel surface with extremely low secondary electron emission characteristics

    NASA Technical Reports Server (NTRS)

    Curren, A. N.; Jensen, K. A.

    1985-01-01

    Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for a range of primary electron beam energies and beam impingement angles are presented for a series of novel textured carbon surfaces on copper substrates. (All copper surfaces used in this study were oxygen-free, high-conductivity grade). The purpose of this investigation is to provide information necessary to develop high-efficiency multistage depressed collectors (MDC's) for microwave amplifier traveling-wave tubes (TWT's) for communications and aircraft applications. To attain the highest TWT signal quality and overall efficiency, the MDC electrode surface must have low secondary electron emission characteristics. While copper is the material most commonly used for MDC electrodes, it exhibits relatively high levels of secondary electron emission unless its surface is treated for emission control. The textured carbon surface on copper substrate described in this report is a particularly promising candidate for the MDC electrode application. Samples of textured carbon surfaces on copper substrates typical of three different levels of treatment are prepared and tested for this study. The materials are tested at primary electron beam energies of 200 to 2000 eV and at direct (0 deg) to near-grazing (85 deg) beam impingement angles. True secondary electron emission and relative reflected primary electron yield characteristics of the textured surfaces are compared with each other and with those of untreated copper. All the textured carbon surfaces on copper substrate tested exhibited sharply lower secondary electron emission characteristics than those of an untreated copper surface.

  20. Characteristic emission enhancement in the atmosphere with Rn trace using metal assisted LIBS

    SciTech Connect

    Hashemi, M. M.; Parvin, P. Moosakhani, A.; Mortazavi, S. Z.; Reyhani, A.; Majdabadi, A.; Abachi, S.

    2014-06-15

    Several characteristic emission lines from the metal targets (Cu, Zn and Pb) were investigated in trace presence of radon gas in the atmospheric air, using Q-SW Nd:YAG laser induced plasma inside a control chamber. The emission lines of metal species are noticeably enhanced in (Rn+air), relative to those in the synthetic air alone. Similar spectra were also taken in various sub-atmospheric environments in order to determine the optimum pressure for enhancement. Solid-state nuclear track detectors were also employed to count the tracks due to alpha particles for the activity assessment.

  1. Characteristic emission enhancement in the atmosphere with Rn trace using metal assisted LIBS

    NASA Astrophysics Data System (ADS)

    Hashemi, M. M.; Parvin, P.; Moosakhani, A.; Mortazavi, S. Z.; Majdabadi, A.; Reyhani, A.; Abachi, S.

    2014-06-01

    Several characteristic emission lines from the metal targets (Cu, Zn and Pb) were investigated in trace presence of radon gas in the atmospheric air, using Q-SW Nd:YAG laser induced plasma inside a control chamber. The emission lines of metal species are noticeably enhanced in (Rn+air), relative to those in the synthetic air alone. Similar spectra were also taken in various sub-atmospheric environments in order to determine the optimum pressure for enhancement. Solid-state nuclear track detectors were also employed to count the tracks due to alpha particles for the activity assessment.

  2. Evaluation of sludge characteristics and metals emissions from municipal sewage sludge incinerators

    SciTech Connect

    Hart, R.S.; Conklin, J.A.; Munn, B.G.

    1996-12-31

    The United States Environmental Protection Agency (USEPA) has promulgated regulations affecting the disposal of municipal sewage sludge under Title 40 of the Code of Federal Regulation (CFR) Part 503. The paper addresses emissions requirements for sewage sludge incineration under 40 CFR Part 503, Subpart E. The paper focuses on factors that may influence sewage sludge characteristics, sewage sludge metals feed rates, and the corresponding metals emission rates. Emissions test programs were conducted at three municipal wastewater treatment plants (WWTP), City of Auburn WWTP. City of Glens Falls WWTP, and Saratoga County Sewer District No. 1 WWTP, to determine mass emissions of multiple metals (As, Be, Cd, Cr, Cu, Pb, Ni, Hg, Se, and Zn). The influent incinerator sludge was sampled in conjunction with each test program to determine the sludge metals content. The sewage sludge was analyzed in accordance with USEPA Method SW846. Multiple metals emissions were determined in accordance with USEPA 40 CFR 60, Appendix A, Method 29 sampling and analytical procedures. The results from these test programs were analyzed to identify the factors that influence the metals emission rates. The resulting metals removal efficiencies from each of the three pollution control systems are quantified. Unique analytical issues encountered during these test programs are also addressed. 7 refs., 3 tabs.

  3. Emission characteristics of particulate matter and volatile organic compounds in cow dung combustion.

    PubMed

    Park, Duckshin; Barabad, Mona L; Lee, Gwangjae; Kwon, Soon-Bark; Cho, Youngmin; Lee, Duckhee; Cho, Kichul; Lee, Kiyoung

    2013-11-19

    Biomass fuel is used for cooking and heating, especially in developing countries. Combustion of biomass fuel can generate high levels of indoor air pollutants, including particulate matter (PM) and volatile organic compounds (VOCs). This study characterized PM and VOC emissions from cow dung combustion in a controlled experiment. Dung from grass-fed cows was dried and combusted using a dual-cone calorimeter. Heat fluxes of 10, 25, and 50 kW/m(2) were applied. The concentrations of PM and VOCs were determined using a dust spectrometer and gas chromatography/mass spectrometry, respectively. PM and VOC emission factors were much higher for the lower heat flux, implying a fire ignition stage. When the heat flux was 50 kW/m(2), the CO2 emission factor was highest and the PM and VOC emission factors were lowest. Particle concentrations were highest in the 0.23-0.3 μm size range at heat fluxes of 25 and 50 kW/m(2). Various toxic VOCs, including acetone, methyl ethyl ketone, benzene, and toluene, were detected at high concentrations. Although PM and VOC emission factors at 50 kW/m(2) were lower, they were high enough to cause extremely high indoor air pollution. The characteristics of PM and VOC emissions from cow dung combustion indicated potential health effects of indoor air pollution in developing countries. PMID:24180364

  4. Characteristics and reactivity of volatile organic compounds from non-coal emission sources in China

    NASA Astrophysics Data System (ADS)

    He, Qiusheng; Yan, Yulong; Li, Hongyan; Zhang, Yiqiang; Chen, Laiguo; Wang, Yuhang

    2015-08-01

    Volatile organic compounds (VOCs) were sampled from non-coal emission sources including fuel refueling, solvent use, industrial and commercial activities in China, and 62 target species were determined by gas chromatography-mass selective detector (GC-MSD). Based on the results, source profiles were developed and discussed from the aspects of composition characteristics, potential tracers, BTEX (benzene, toluene, ethylbenzene and xylene) diagnostic ratios and chemical reactivity. Compared with vehicle exhausts and liquid fuels, the major components in refueling emissions of liquefied petroleum gas (LPG), gasoline and diesel were alkenes and alkanes. Oppositely, aromatics were the most abundant group in emissions from auto-painting, book binding and plastic producing. Three groups contributed nearly equally in printing and commercial cooking emissions. Acetone in medical producing, chloroform and tetrachloroethylene in wet- and dry-cleaning, as well as TEX in plastic producing etc. were good tracers for the respective sources. BTEX ratios showed that some but not all VOCs sources could be distinguished by B/T, B/E and B/X ratios, while T/E, T/X and E/X ratios were not suitable as diagnostic indicators of different sources. The following reactivity analysis indicated that emissions from gasoline refueling, commercial cooking, auto painting and plastic producing had high atmospheric reactivity, and should be controlled emphatically to prevent ozone pollution, especially when there were large amounts of emissions for them.

  5. [Source emission characteristics of malodorous volatile organic carbonyls from a municipal sewage treatment plant].

    PubMed

    Zhou, Mi; Wang, Bo-Guang; Zhao, De-Jun; Zhang, Chun-Lin; Gu, Yin-Gang

    2011-12-01

    A 4-day field observation was conducted at Liede sewage treatment plant in Guangzhou, using PFPH/GC/MS method to analyse the composition and the concentration of volatile carbonyl compounds, and investigate the source emission characteristics of the pollutants. The results were as follows: 18 carbonyl species were detected, which including 15 malodorous volatile carbonyls with a concentration range from 0.39 microg x m(-3) to 19.92 microg x m(-3) at six processing units. Mean value of the total malodorous volatile carbonyls was (68.66 +/- 10.05) microg x m(-3). Normalization data process was used to research the source emission profile for malodorous volatile carbonyls, formaldehyde, acetaldehyde, propionaldehyde, 2-butanone, butyraldehyde and hexaldehyde were found to be molecular markers of the source emission with their percentage of total carbonyls up to 78.91%. Hexaldehyde was the most abundant carbonyl species with an average concentration of 11.71 microg x m(-3). Using a calculation model of area source emission, it estimated that the total annual emissions of the municipal sewage treatment plant was 2 302.33 kg(-1), and the contribution ratio of each processing unit was in an order of biochemical reaction basin, concentration basin, grade A aeration, ascending pump room, grit basin, dewatering house. The malodorous emission of sewage treatment plant is affected by many complex factors, so there's some uncertainty on the estimate. PMID:22468520

  6. Effects of diesel engine speed and water content on emission characteristics of three-phase emulsions.

    PubMed

    Lin, Cherng-Yuan; Wang, Kuo-Hua

    2004-01-01

    The effects of water content of three-phase emulsions and engine speed on the combustion and emission characteristics of diesel engines were investigated in this study. The results show that a larger water content of water-in oil (W/O) and oil-in-water-in-oil (O/W/O) emulsion caused a higher brake specific fuel consumption (bsfc) value and a lower O2, as well as a lower NOx emission, but a larger CO emission. The increase in engine speed resulted in an increase of bsfc, exhaust gas temperature, fuel-to-air ratio, CO2 emission and a decrease of NOx, CO emission, and smoke opacity. Because of the physical structural differences, the three-phase O/W/O emulsions were observed to produce a higher exhaust gas temperature, a higher emulsion viscosity and a lower CO emission, in comparison with that of the two-phase W/O emulsion. In addition, the use of W/O emulsions with water content larger than 20% may cause diesel engines to shut down earlier than those running on O/W/O emulsions with the same water content. Hence, it is suggested that the emulsions with water content larger than 20% are not suitable for use as alternative fuel for diesel engines. PMID:15137702

  7. Pollutant emission characteristics of rice husk combustion in a vortexing fluidized bed incinerator.

    PubMed

    Duan, Feng; Chyang, Chiensong; Chin, Yucheng; Tso, Jim

    2013-02-01

    Rice husk with high volatile content was burned in a pilot scale vortexing fluidized bed incinerator. The fluidized bed incinerator was constructed of 6 mm stainless steel with 0.45 m in diameter and 5 m in height. The emission characteristics of CO, NO, and SO2 were studied. The effects of operating parameters, such as primary air flow rate, secondary air flow rate, and excess air ratio on the pollutant emissions were also investigated. The results show that a large proportion of combustion occurs at the bed surface and the freeboard zone. The SO2 concentration in the flue gas decreases with increasing excess air ratio, while the NOx concentration shows reverse trend. The flow rate of secondary air has a significant impact on the CO emission. For a fixed primary air flowrate, CO emission decreases with the secondary air flowrate. For a fixed excess air ratio, CO emission decreases with the ratio of secondary to primary air flow. The minimum CO emission of 72 ppm is attained at the operating condition of 40% excess air ratio and 0.6 partition air ratio. The NOx and SO2 concentrations in the flue gas at this condition are 159 and 36 ppm, which conform to the EPA regulation of Taiwan. PMID:23596954

  8. Material and energy recovery in integrated waste management systems: an innovative approach for the characterization of the gaseous emissions from residual MSW bio-drying.

    PubMed

    Ragazzi, M; Rada, E C; Antolini, D

    2011-01-01

    In the sector of residual municipal solid waste management an increasing attention is put towards the role of biological treatments like bio-drying and bio-stabilization in order to decrease the need of landfilling volumes. The literature shows a lack of information concerning the emission factor of pollutants released from these processes. The available data are generally spot characterizations of concentration and air flow-rate that are used together in order to assess the emission factors. This approach caused significant differences among the available data as the release of pollutants is not steady. This paper belongs to a group of six papers concerning a research on material and energy recovery in integrated waste management systems, developed by a network of five universities. The contribution of the University of Trento, focuses on the bio-drying process with the following targets: (a) developing an innovative low cost method of sampling/measurement able to take into account the dynamics of release of pollutants; (b) checking the efficiency of a bio-filter; (c) verifying the variability of generation of some pollutants; (d) generating emission factors. The research was developed using a bio-drying pilot plant. As a treatment of the process air, the bio-reactor was coupled with a bio-filter. The emissions were characterized using an original approach based on the adoption of two measurement chambers suitable for hosting passive samplers. The passive samplers allowed the characterization of VOCs, N(2)O, NH(3) and H(2)S. A bio-chemical model, useful for energy and mass balances, supported the interpretation of the presented bio-drying run. PMID:21482095

  9. Material and energy recovery in integrated waste management systems: An innovative approach for the characterization of the gaseous emissions from residual MSW bio-drying

    SciTech Connect

    Ragazzi, M.; Rada, E.C.; Antolini, D.

    2011-09-15

    In the sector of residual municipal solid waste management an increasing attention is put towards the role of biological treatments like bio-drying and bio-stabilization in order to decrease the need of landfilling volumes. The literature shows a lack of information concerning the emission factor of pollutants released from these processes. The available data are generally spot characterizations of concentration and air flow-rate that are used together in order to assess the emission factors. This approach caused significant differences among the available data as the release of pollutants is not steady. This paper belongs to a group of six papers concerning a research on material and energy recovery in integrated waste management systems, developed by a network of five universities. The contribution of the University of Trento, focuses on the bio-drying process with the following targets: (a) developing an innovative low cost method of sampling/measurement able to take into account the dynamics of release of pollutants; (b) checking the efficiency of a bio-filter; (c) verifying the variability of generation of some pollutants; (d) generating emission factors. The research was developed using a bio-drying pilot plant. As a treatment of the process air, the bio-reactor was coupled with a bio-filter. The emissions were characterized using an original approach based on the adoption of two measurement chambers suitable for hosting passive samplers. The passive samplers allowed the characterization of VOCs, N{sub 2}O, NH{sub 3} and H{sub 2}S. A bio-chemical model, useful for energy and mass balances, supported the interpretation of the presented bio-drying run.

  10. Using broiler litter and swine manure lagoon effluent in sawdust-based swine mortality composts: Effects on nutrients, bacteria, and gaseous emissions.

    PubMed

    McLaughlin, M R; Brooks, J P; Adeli, A; Miles, D M

    2015-11-01

    Disposition of mortalities challenges confined animal feeding operations (CAFOs), especially sow (farrowing) farms, which experience mortalities daily. Regulations and transportation costs may preclude incineration, landfill burial, and rendering; therefore, swine CAFOs in Mississippi in the Mid-South U.S. often compost mortalities. In this study, a farm-standard composting mix of sawdust (S) and water (W) was compared with mixes where N was supplied by broiler litter (L) and water was replaced with swine lagoon effluent (E). The objective was to assess the effects of these manure byproducts: 1) on nutrients and bacteria in composts destined for land application; and 2) on emissions of ammonia and greenhouse gases. Three replications of four mixes (SW, SLW, SE, SLE) were compared in microcosms comprising modified plastic recycling bins. The experiment was repeated three times in different seasons in one year. Mixes were compared for differences in temperature, water content, nutrients (C, N, P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn), bacteria (Gram-, Gram+, Clostridium perfringens, Salmonella, Listeria, Escherichia coli), and emissions (NH3, CO2, CH4, N2O). Litter addition increased composting temperatures initially and after aerations; increased nutrient concentrations, except C, in start mixes and all except C and N, in finish mixes; increased Gram+ bacteria, Salmonella, and E. coli in start mixes, but only Gram+s in finish mixes; and increased emissions. Effluent addition increased early composting temperatures; had no effect on nutrients or bacteria, except increased C. perfringens in start, but not finish mixes; and had no effect on emissions. Nutrients in finish composts did not differ among mixes for N (average 3.3%), but litter composts had more P and K, and lower N:P than composts without litter. Improving mortality composting is of global importance as increasing livestock populations and intensive animal production systems require practical, safe

  11. Emission characteristics of modern and old-type residential boilers fired with wood logs and wood pellets

    NASA Astrophysics Data System (ADS)

    Johansson, Linda S.; Leckner, Bo; Gustavsson, Lennart; Cooper, David; Tullin, Claes; Potter, Annika

    Emissions from commercial residential boilers fired with wood logs and wood pellets, have been compared. Seven boilers, selected with respect to age, design, connection to heat storage tank, and type of biofuel, were included in the study, which also covers two oil-fired boilers in comparison. The measurements of gaseous emissions comprised carbon monoxide (CO), carbon dioxide (CO 2), oxygen (O 2), total organic carbons (TOC), nitrogen oxides (NO x), polycyclic aromatic hydrocarbons (PAH), and 33 volatile organic compounds (VOC). Particle emissions were characterised by mass concentration, number concentration, and the corresponding particle size distributions. In general, old-type wood boilers caused considerably higher emissions than modern wood and pellet boilers. The mass concentration of particles was 180 times larger in the worst old-type case (a water-cooled wood boiler without heat storage tank) compared to the best modern case (wood pellets). The TOC emission was shown to be correlated to the CO emission, both ranging between very low values and up to 10 000 mg/MJ, depending on design and operation. The highest emissions of unoxidised compounds occurred at the highest excess air ratio, and oxygen was not the limiting parameter for poor combustion. Instead, high excess air can be suspected to cool the combustion chamber, resulting in high CO emissions. VOC was dominated by methane. Especially from an old-type boiler the methane emissions could be high and the effect on climate change then may become larger than that of an oil boiler. However, substitution of an old-type wood boiler with a modern wood boiler attached to a storage tank or with a pellet boiler, would reduce methane emissions by 8 to 9000 times and the efficiency would increase. Most emissions could be considerably lowered by connecting the old-type wood boiler to a heat storage tank, or by charging small (in relation to the combustion chamber) batches of wood.

  12. Performance, emissions, and physical characteristics of a rotating combustion aircraft engine

    NASA Technical Reports Server (NTRS)

    Berkowitz, M.; Hermes, W. L.; Mount, R. E.; Myers, D.

    1976-01-01

    The RC2-75, a liquid cooled two chamber rotary combustion engine (Wankel type), designed for aircraft use, was tested and representative baseline (212 KW, 285 BHP) performance and emissions characteristics established. The testing included running fuel/air mixture control curves and varied ignition timing to permit selection of desirable and practical settings for running wide open throttle curves, propeller load curves, variable manifold pressure curves covering cruise conditions, and EPA cycle operating points. Performance and emissions data were recorded for all of the points run. In addition to the test data, information required to characterize the engine and evaluate its performance in aircraft use is provided over a range from one half to twice its present power. The exhaust emissions results are compared to the 1980 EPA requirements. Standard day take-off brake specific fuel consumption is 356 g/KW-HR (.585 lb/BHP-HR) for the configuration tested.

  13. The characteristics of performance and exhaust emissions of a diesel engine using a biodiesel with antioxidants.

    PubMed

    Ryu, Kyunghyun

    2010-01-01

    The aim of this study is to investigate the effects of antioxidants on the oxidation stability of biodiesel fuel, the engine performance and the exhaust emissions of a diesel engine. Biodiesel fuel used in the study was derived from soybean oil. The results show that the efficiency of antioxidants is in the order TBHQ>PrG>BHA>BHT>alpha-tocopherol. The oxidative stability of biodiesel fuel attained the 6-h quality standard with 100 ppm TBHQ and with 300 ppm PrG in biodiesel fuel. Combustion characteristics and exhaust emissions in diesel engine were not influenced by the addition of antioxidants in biodiesel fuel. The BSFC of biodiesel fuel with antioxidants decreased more than that of biodiesel fuel without antioxidants, but no trends were observed according to the type or amount of antioxidant. Antioxidants had few effects on the exhaust emissions of a diesel engine running on biodiesel. PMID:19525107

  14. Near band edge emission characteristics of sputtered nano-crystalline ZnO films

    NASA Astrophysics Data System (ADS)

    Kunj, Saurabh; Sreenivas, K.

    2016-05-01

    Sputtered zinc oxide (ZnO) thin films deposited on unheated glass substrate under different sputtering gas mixtures (Ar+O2) have been investigated using X-ray diffraction and photo luminescence spectroscopy. Earlier reported studies on ZnO films prepared by different techniques exhibit either a sharp/broad near band edge (NBE) emission peak depending on the crystalline quality of the film. In the present study zinc oxide films, grown on unheated substrates, are seen to possess a preferred (002) orientation with a microstructure consisting of clustered nano-sized crystallites. The splitting in the near band edge emission (NBE) into three characteristic peaks is attributed to quantum confinement effect, and is observed specifically under an excitation of 270 nm. Deep level emission (DLE) in the range 400 to 700 nm is not observed indicating absence of deep level radiative defects.

  15. A study on the performance and emission characteristics of esterified pinnai oil tested in VCR engine.

    PubMed

    Ashok Kumar, T; Chandramouli, R; Mohanraj, T

    2015-11-01

    Biodiesel is a clean renewable fuel derived from vegetable oils and animal fats. It is biodegradable, oxygenated, non toxic and free from sulfur and aromatics. The biodiesel prepared from pinnai oil undergoes acid esterification followed by alkaline transesterification process. The fatty acid methyl esters components were identified using gas chromatography and compared with the standard properties. The properties of biodiesel are comparable with diesel. The yield of the biodiesel production depends upon the process parameters such as reaction temperature, pH, time duration and amount of catalyst. The yield of biodiesel by transesterification process was 73% at 55°C. This fuel was tested in a variable compression ratio engine with blend ratios of B10 and B20. During the test runs the compression ratio of the engine was varied from 15:1 to 18:1 and the torque is adjusted from zero to maximum value of 22Nm. The performance characteristics such as the brake thermal efficiency, brake specific energy consumption and exhaust gas temperature of the engine are analyzed. The combustion characteristics of biodiesel like ignition delay, combustion duration and maximum gas temperature and the emission characteristics are also analyzed. The performance characteristics, combustion characteristics and engine emission are effective in the variable compression ratio engine with biodiesel and it is compared with diesel. PMID:26116080

  16. Effects of operating pressure on flame oscillation and emission characteristics in a partially premixed swirl combustor

    SciTech Connect

    Kim, Jong-Ryul; Choi, Gyung-Min; Kim, Duck-Jool

    2011-01-15

    The influence of varying combustor pressure on flame oscillation and emission characteristics in the partially premixed turbulent flame were investigated. In order to investigate combustion characteristics in the partially premixed turbulent flame, the combustor pressure was controlled in the range of -30 to 30 kPa for each equivalence ratio ({phi} = 0.8-1.2). The r.m.s. of the pressure fluctuations increased with decreasing combustor pressure for the lean condition. The combustor pressure had a sizeable influence on combustion oscillation, whose dominant frequency varied with the combustor pressure. Combustion instabilities could be controlled by increasing the turbulent intensity of the unburned mixture under the lean condition. An unstable flame was caused by incomplete combustion; hence, EICO greatly increased. Furthermore, EINO{sub x} simply reduced with decreasing combustor pressure at a rate of 0.035 g/10 kPa. The possibility of combustion control on the combusting mode and exhaust gas emission was demonstrated. (author)

  17. Emission and surface characteristic of ternary alloy Ir/Re/W-coated impregnated tungsten cathodes

    NASA Astrophysics Data System (ADS)

    Zhang, Honglai; Liu, Yanwen; Zhang, Mingchen; Li, Yutao

    2005-09-01

    In order to improve the activation characteristics and emission ability of the conventional Ir-coated impregnated tungsten cathodes, a new type of dispenser cathode with ternary alloy Ir/Re/W coating was developed. The improved cathodes show higher emission current density and faster activation characteristics than that of the conventional pure Ir-coated impregnated tungsten cathodes. X-ray photoelectron spectroscopy (XPS) was used to analyze the element compositions on the surface of the cathodes coated with pure Ir and Ir/Re/W alloy. The results show that for pure Ir coating cathode, binary alloy (Ir/W) is formed. The surface atom concentration is near 50/50 after full activation. For ternary alloy coating cathode, the surface atom concentration has changed from 35%Ir-25%Re-40%W to 33%Ir-19%Re-48%W before and after activation.

  18. Performance and emissions characteristics of a naturally aspirated diesel engine with vegetable oil fuels - 2

    SciTech Connect

    Humke, A.L.; Barsic, N.J.

    1981-01-01

    A naturally aspirated, direct injected diesel engine was used to evaluate the performance and emissions characteristics of a crude soybean oil, a 50 percent (by volume) mixture of crude soybean oil and no. 2 diesel fuel, and a degummed soybean oil. The data were compared with previous tests conducted on the same engine using diesel fuel, crude sunflower oil and a 50 percent mixture of crude sunflower oil and diesel fuel. 18 refs.

  19. Effects of methane on giant planet’s UV emissions and implications for the auroral characteristics

    NASA Astrophysics Data System (ADS)

    Gustin, J.; Gérard, J.-C.; Grodent, D.; Gladstone, G. R.; Clarke, J. T.; Pryor, W. R.; Dols, V.; Bonfond, B.; Radioti, A.; Lamy, L.; Ajello, J. M.

    2013-09-01

    This study reviews methods used to determine important characteristics of giant planet’s UV aurora (brightness, energy of the precipitating particles, altitude of the emission peak,…), based on the absorbing properties of methane and other hydrocarbons. Ultraviolet aurorae on giant planets are mostly caused by inelastic collisions between energetic magnetospheric electrons and the ambient atmospheric H2 molecules. The auroral emission is situated close to a hydrocarbon layer and may be attenuated by methane (CH4), ethane (C2H6) and acetylene (C2H2) at selected wavelengths. As methane is the most abundant hydrocarbon, it is the main UV absorber and attenuates the auroral emission shorward of 1350 Å. The level of absorption is used to situate the altitude/pressure level of the aurora, hence the energy of the precipitated electrons, whose penetration depth is directly related to their mean energy. Several techniques are used to determine these characteristics, from the color ratio method which measures the level of absorption from the ratio between an absorbed and an unabsorbed portion of the observed auroral spectrum, to more realistic methods which combine theoretical distributions of the precipitating electrons with altitude dependent atmospheric models. The latter models are coupled with synthetic or laboratory H2 spectra and the simulated emergent spectra are compared to observations to determine the best auroral characteristics. Although auroral characteristics may be very variable with time and locations, several typical properties may be highlighted from these methods: the Jovian aurora is the most powerful, with brightness around 120 kR produced by electrons of mean energy ∼100 keV and an emission situated near the 1 μbar level (∼250 km above the 1 bar level) while Saturn’s aurora is fainter (∼10 kR), produced by electrons less than 20 keV and situated near the 0.2 μbar level (∼1100 km).

  20. Field Emission Characteristics of Carbon Nanotubes and Their Applications in Sensors and Devices

    NASA Astrophysics Data System (ADS)

    Vaseashta, Ashok

    2003-03-01

    FIELD EMISSION CHARACTERISTICS OF CARBON NANOTUBES AND THEIR APPLICATIONS IN SENSORS AND DEVICES A. Vaseashta, C. Shaffer, M. Collins, A. Mwuara Dept of Physics, Marshall University, Huntington, WV V. Pokropivny Institute for Materials Sciences of NASU, Kiev, Ukraine. D. Dimova-Malinovska Bulgarian Academy of Sciences, Sofia, Bulgaria. The dimensionality of a system has profound influence on its physical behavior. With advances in technology over the past few decades, it has become possible to fabricate and study reduced-dimensional systems, such as carbon nanotubes (CNTs). Carbon nanotubes are especially promising candidate for cold cathode field emitter because of their electrical properties, high aspect ratio, and small radius of curvature at the tips. Electron emission from the carbon nanotubes was investigated. Based upon the field emission investigation of carbon nanotubes, several prototype devices have been suggested that operate with low swing voltages with sufficient high current densities. Characteristics that allow improved current stability and long lifetime operation for electrical and opto-electronics devices are presented. The aim of this brief overview is to illustrate the useful characteristics of carbon nanotubes and its possible application.

  1. Electron reflection and secondary emission characteristics of sputter-textured pyrolytic graphite surfaces

    NASA Technical Reports Server (NTRS)

    Wintucky, E. G.; Curren, A. N.; Sovey, J. S.

    1981-01-01

    Measurements are presented of secondary electron emission and reflected primary electron characteristics of sputter-textured pyrolitic graphite surfaces with microstructures of various sizes and densities, made with an Auger cylindrical mirror analyzer in a high-vacuum chamber at pressures below 1.33 x 10 to the -7th N/sq m (10 to the -9th torr). A dense, tall, thin, spire-like microstructure, obtained at ion energies of 1000 eV and ion current densities of 5 mA/sq cm, is the most effective. The secondary electron emission from such a surface is lower than that of soot, whose secondary emission is among the lowest of any material. At a primary electron energy of 1000 eV, the secondary electron emission yield of smooth CU is about 350% greater than the lowest value obtained for sputter-textured pyrolitic graphite. The reflected primary electron index of smooth Cu is a factor of 80 greater. If the secondary electron emission yield is reduced to 0.3, which is possible with sputter-textured pyrolitic graphite, the traveling wave tube collector efficiency could be improved by as much as 4% over that for smooth copper.

  2. Emission characteristics of heavy metals and their behavior during coking processes.

    PubMed

    Mu, Ling; Peng, Lin; Liu, Xiaofeng; Bai, Huiling; Song, Chongfang; Wang, Ying; Li, Zhen

    2012-06-01

    Besides organic pollutants, coke production generates emissions of toxic heavy metals. However, intensive studies on heavy metal emissions from the coking industry are still very scarce. The current work focuses on assessing the emission characteristics of heavy metals and their behavior during coking. Simultaneous sampling of coal, coke, residues from air pollution control devices (APCD), effluent from coke quenching, and fly ash from different processes before and after APCD has been performed. The total heavy metal concentration in the flue gas from coke pushing (CP) was significantly higher than that from coal charging (CC) and combustion of coke oven gases (CG). Emission factors of heavy metals for CP and CC were 378.692 and 42.783 μg/kg, respectively. During coking, the heavy metals that were contained in the feedstock coal showed different partitioning patterns. For example, Cu, Zn, As, Pb, and Cr were obviously concentrated in the inlet fly ash compared to the coke; among these metals Cu, As, and Cr were concentrated in the outlet fly ash, whereas Zn and Pb were distributed equally between the outlet fly ash and APCD residue. Ni, Co, Cd, Fe, and V were partitioned equally between the inlet fly ash and the coke. Understanding the behavior of heavy metals during coking processes is helpful for the effective control of these heavy metals and the assessment of the potential impact of their emissions on the environment. PMID:22607524

  3. Field emission characteristics of zinc oxide nanowires synthesized by vapor-solid process

    PubMed Central

    2014-01-01

    Vertically aligned ZnO nanowire (NW) arrays have been synthesized on silicon substrates by chemical vapor deposition. The growth of ZnO NWs may be dominated by vapor-solid nucleation mechanism. Morphological, structural, optical, and field emission characteristics can be modified by varying the growth time. For growth time that reaches 120 min, the length and diameter of ZnO NWs are 1.5 μm and 350 nm, respectively, and they also show preferential growth orientation along the c-axis. Room-temperature photoluminescence spectra exhibit a sharp UV emission and broad green emission, and the enhanced UV-to-green emission ratio with increasing growth time might originate from the reduced concentration of surface defects. Furthermore, strong alignment and uniform distribution of ZnO NWs can also effectively enhance the antireflection to reach the average reflectance of 5.7% in the visible region. The field emission measurement indicated that the growth time plays an important role in density- and morphology-controlled ZnO NWs, and thus, ZnO NWs are expected to be used in versatile optoelectronic devices. PMID:24517113

  4. [Emission Characteristics of Water-Soluble Ions in Fumes of Coal Fired Boilers in Beijing].

    PubMed

    Hu, Yue-qi; Ma, Zhao-hui; Feng, Ya-jun; Wang, Chen; Chen, Yuan-yuan; He, Ming

    2015-06-01

    Selecting coal fired boilers with typical flue gas desulfurization and dust extraction systems in Beijing as the study objects, the issues and characteristics of the water-soluble ions in fumes of coal fired boilers and theirs influence factors were analyzed and evaluated. The maximum mass concentration of total water-soluble ions in fumes of coal fired boilers in Beijing was 51.240 mg x m(-3) in the benchmark fume oxygen content, the minimum was 7.186 mg x m(-3), and the issues of the water-soluble ions were uncorrelated with the fume moisture content. SO4(2-) was the primary characteristic water-soluble ion for desulfurization reaction, and the rate of contribution of SO4(2-) in total water-soluble ions ranged from 63.8% to 81.0%. F- was another characteristic water-soluble ion in fumes of thermal power plant, and the rate of contribution of F- in total water-soluble ions ranged from 22.2% to 32.5%. The fume purification technologies significantly influenced the issues and the emission characteristics of water-soluble ions in fumes of coal fired boilers. Na+ was a characteristic water-soluble ion for the desulfurizer NaOH, NH4+ and NO3+ were characteristic for the desulfurizer NH4HCO3, and Mg2+ was characteristic for the desulfurizer MgO, but the Ca2+ emission was not increased by addition of the desulfurizer CaO or CaCO3 The concentrations of NH4+ and NO3- in fumes of thermal power plant were lower than those in fumes of industrial or heating coal fired boilers. The form of water-soluble ions was significantly correlated with fume temperature. The most water-soluble ions were in superfine state at higher fume temperature and were not easily captured by the filter membrane. PMID:26387296

  5. Gaseous fuel reactors for power systems

    NASA Technical Reports Server (NTRS)

    Kendall, J. S.; Rodgers, R. J.

    1977-01-01

    Gaseous-fuel nuclear reactors have significant advantages as energy sources for closed-cycle power systems. The advantages arise from the removal of temperature limits associated with conventional reactor fuel elements, the wide variety of methods of extracting energy from fissioning gases, and inherent low fissile and fission product in-core inventory due to continuous fuel reprocessing. Example power cycles and their general performance characteristics are discussed. Efficiencies of gaseous fuel reactor systems are shown to be high with resulting minimal environmental effects. A technical overview of the NASA-funded research program in gaseous fuel reactors is described and results of recent tests of uranium hexafluoride (UF6)-fueled critical assemblies are presented.

  6. [Situation and Characteristics of Air Pollutants Emission from Crematories in Beijing, China].

    PubMed

    Xue, Yi-feng; Yan, Jing; Tian, He-zhong; Xiong, Cheng-cheng; Li, Jing-dong; Wu, Xiao-ing; Wang, Wei

    2015-06-01

    Hazardous Air Pollutants (HAPs) such as exhaust particulate matter (PM), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxide (NOx), mercury (Hg) and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans ( PCDD/Fs) are emitted by the process of cremation and the burning of oblation. Risks to health posed by emissions of hazardous air pollutants from crematories are emerging concerns. Through field investigation and data collection, we obtained the related activity levels and monitored the concentrations of air pollutants from typical cremators, so as to better understand the current pollutants emission levels for crematory. Using the emission factor method, we calculated the emission inventory of HAPs for crematory of Beijing in 2012 and quantified the range of uncertainty. Using atmospheric diffusion model ADMS, we evaluated the influence of crematories on the surrounding environment, and identified the characteristics of air pollution. The results showed that: for the cremators installed with flue gas purification system, the emission concentration of exhaust PM was rather low, and the CO emission concentration fluctuated greatly. However, relative high emission concentrations of PCDD/Fs were detected mainly due to insufficient combustion. Exhaust PM, CO, SO2, NOx, Hg and PCDD/Fs emitted by crematory of Beijing in 2012 were estimated at about 11. 5 tons, 41.25 tons, 2.34 tons, 7.65 tons, 13.76 kg and 0.88 g, respectively; According to the results of dispersion model simulation, the concentration contributions of exhaust PM, CO, SO2, NOx, Hg, PCDD/Fs from crematories were 0.05947 microg x m(-3), 0.2009 microg x m(-3) and 0.0126 microg x m(-3), 0.03667 microg x m(-3) and 0.06247 microg x m(-3), 0.004213 microg x m(-3), respectively. PMID:26387295

  7. Characteristics and photochemical potentials of volatile organics emission from stack exhaust gas of industrial processes

    SciTech Connect

    Hsu, Y.C.; Tsai, J.H.; Lin, T.C.; Cheng, C.C.; Huang, Y.H.

    1999-07-01

    The main objective of this project was to measure the main volatile organic compounds (VOCs) in stack gas from the downstream petrochemical plants. Six pollution sources of industrial processes, including Acrylonitrile-Butadiene-Styrene (ABS), Vinyl Chloride(VC), Polyvinyl Chloride (PVC), Acrylic Resin, para-Terephthalic Acid (PTA) and Polyurethane (PU) synthetic manufacturing processes, were measured by using USEPA Method 18. The concentration and emission rate database of twenty-seven VOCs has been established. Fifty-two selected stacks were sampled and analyzed for VOCs. Analysis of emission factors and characteristics of the twenty-seven VOCs in these stacks show that the emission characteristics are various among different industrial processes. The order of the single-stack VOCs average emission factor are ABS (1.109 lbs VOCs/ton-ABS; 22 stacks) {gt} Acrylic Resin (0.651 lbs VOCs/ton-acrylic resin; 7 stacks) {gt} PU Synthetic (0.606 lbs VOCs/ton-PU synthetic; 4 stacks) {gt} PTA (0.054 lbs VOCs/ton-PTA; 4 stacks) {gt} PVC (0.014 lbs VOCs/ton-PVC; 11 stacks) {gt} VC ({lt} 0.001; 4 stacks) manufacturing processes. The emission factors of VOC in AP-42 database for the processes of are 5 to 40 times higher than those of VOCs in this research. Because of the equipment of pollutant control setting up before the emitted exhaust gas, their average emission factors in these measured processes are almost lower than those of VOCs in AP-42 database. Compared with the characteristics of VOCs, there is little similarity in VOC characteristics for the stacks of six processes between the results from this research and the data from US EPA SPECIATE data system. Furthermore, according to maximum incremental reactivities (MIR) of VOCs probed into photochemical reaction potentials, the results show that those of PTA manufacturing process have an ozone formation potential of 2.33 g O{sub 3}/g VOCs, which is higher than other processes.

  8. Soil Pore Characteristics, an Underappreciated Regulatory Factor in GHGs Emission and C Stabilization

    NASA Astrophysics Data System (ADS)

    Toosi, E. R.; Yu, J.; Doane, T. A.; Guber, A.; Rivers, M. L.; Marsh, T. L.; Ali, K.; Kravchenko, A. N.

    2015-12-01

    Enduring challenges in understanding soil organic matter (SOM) stability and emission of greenhouse gases (GHGs) from soil stem from complexities of soil processes, many of which occur at micro-scales. The goal of this study is to evaluate the interactive effects soil pore characteristics, soil moisture levels, inherent SOM levels and properties, and substrate quality, on GHGs emission, and accelerated decomposition of native SOM following addition of fresh substrate i.e. priming. Our core hypothesis is that soil pore characteristics play a major role as a mediator in (i) the decomposition of organic matter regardless of its source (i.e. litter vs. native SOM) or substrate quality, as well as in (ii) GHGs emissions. Samples with prevalence of small (<10 μm) vs. large (>30 μm) pores were prepared from soils with similar properties but under long-term contrasting management. The samples were incubated (110 d) at low and optimum soil moisture conditions after addition of high quality (13C-soybean) and low quality (13C-corn) substrate. Headspace gas was analyzed for 13C-CO2 and GHGs on a regularly basis (day 1, 3, 7, 14, 24, 36, 48, 60, 72, 90, and 110). Selected samples were scanned at the early stage of decomposition (7, 14, 24 d) at 2-6 μm resolutions using X-ray computed μ tomography in order to: (1) quantify soil pore characteristics; (2) visualize and quantify distribution of soil moisture within samples of different pore characteristics; and (3) to visualize and measure losses of decomposing plant residue. Initial findings indicate that, consistent with our hypotheses, pore characteristics influenced GHGs emission, and intensity and pattern of plant residue decomposition. The importance of pores was highly pronounced in presence of added plant residue where greater N2O emission occurred in samples with dominant large pores, in contrast to CO2. Further findings will be discussed upon completion of the study and analysis of the results.

  9. Trends in Concentrations of Atmospheric Gaseous and Particulate Species at the Look Rock, TN NCORE Air Quality Station and Their Relation to Primary Emissions Reductions

    NASA Astrophysics Data System (ADS)

    Tanner, R. L.; Mueller, S. F.; Bairai, S. T.

    2013-12-01

    Air quality parameters, measured at Look Rock, TN, since 1980, were expanded by National Park Service (NPS) as an IMPROVE network station and again in 1999-2007 by Tennessee Valley Authority as part of efforts to determine the effects of reductions in EGU emissions of sulfur and nitrogen oxides on air quality at the site. Designated as a non-urban, NCORE-equivalent station in 2010, routine continuous monitoring of aerosol mass, sulfate, and black carbon, and primary and secondary gases at the site as well as additional measurements during a series of intensive research studies at the site have produced an extensive body to air quality data on background levels of species relevant to air quality standards (NAAQS) for ozone and fine particulate matter which is unique comprehensive for a high-altitude site in the southeastern U.S.A. Analysis of the temporal trends in these data (1999-present)is being conducted in conjunction with and support of 2013 Southern Atmosphere Studies at Look Rock and other southeastern U.S. locations. Key findings from analysis of temporal trends at Look Rock include the observation that primary pollutant levels have consistently tracked the emissions reductions from EGUs and other primary sources in the region, but reductions in secondary pollutants such as particulate sulfate and ozone have been less than proportional. Organic carbonaceous material (OM) remains a major contributor to fine particulate mass at the site, and a large portion (65-85%) of OM derives from modern carbon, based on 14C measurements. Important parameters affecting fine mass and ozone levels also include the specific diurnal meteorology at this ridge-top site, its location in a largely mixed-deciduous forest, and the presence of primary sources of precursors at distances of 50-500 km from the site in all directions.

  10. Greenhouse gas emissions during MSW landfilling in China: influence of waste characteristics and LFG treatment measures.

    PubMed

    Yang, Na; Zhang, Hua; Shao, Li-Ming; Lü, Fan; He, Pin-Jing

    2013-11-15

    Reducing greenhouse gas (GHG) emissions from municipal solid waste (MSW) treatment can be highly cost-effective in terms of GHG mitigation. This study investigated GHG emissions during MSW landfilling in China under four existing scenarios and in terms of seven different categories: waste collection and transportation, landfill management, leachate treatment, fugitive CH4 (FM) emissions, substitution of electricity production, carbon sequestration and N2O and CO emissions. GHG emissions from simple sanitary landfilling technology where no landfill gas (LFG) extraction took place (Scenario 1) were higher (641-998 kg CO2-eq·t(-1)ww) than those from open dump (Scenario 0, 480-734 kg CO2-eq·t(-1)ww). This was due to the strictly anaerobic conditions in Scenario 1. LFG collection and treatment reduced GHG emissions to 448-684 kg CO2-eq·t(-1)ww in Scenario 2 (with LFG flare) and 214-277 kg CO2-eq·t(-1)ww in Scenario 3 (using LFG for electricity production). Amongst the seven categories, FM was the predominant contributor to GHG emissions. Global sensitivity analysis demonstrated that the parameters associated with waste characteristics (i.e. CH4 potential and carbon sequestered faction) and LFG management (i.e. LFG collection efficiency and CH4 oxidation efficiency) were of great importance. A further learning on the MSW in China indicated that water content and dry matter content of food waste were the basic factors affecting GHG emissions. Source separation of food waste, as well as increasing the incineration ratio of mixed collected MSW, could effectively mitigate the overall GHG emissions from landfilling in a specific city. To increase the LFG collection and CH4 oxidation efficiencies could considerably reduce GHG emissions on the landfill site level. While, the improvement in the LFG utilization measures had an insignificant impact as long as the LFG is recovered for energy generation. PMID:24018116

  11. Thermal infrared emissivity spectrum and its characteristics of crude oil slick covered seawater.

    PubMed

    Xiong, Pan; Gu, Xing-Fai; Yu, Taol; Meng, Qing-Yan; Li, Jia-Guoi; Shi, Ji-xiang; Cheng, Yang; Wang, Liang; Liu, Wen-Song; Liu, Qi-Yuei; Zhao, Li-Min

    2014-11-01

    Detecting oil slick covered seawater surface using the thermal infrared remote sensing technology exists the advantages such as: oil spill detection with thermal infrared spectrum can be performed in the nighttime which is superior to visible spectrum, the thermal infrared spectrum is superior to detect the radiation characteristics of both the oil slick and the seawater compared to the mid-wavelength infrared spectrum and which have great potential to detect the oil slick thickness. And the emissivity is the ratio of the radiation of an object at a given temperature in normal range of the temperature (260-320 K) and the blackbody radiation under the same temperature , the emissivity of an object is unrelated to the temperature, but only is dependent with the wavelength and material properties. Using the seawater taken from Bohai Bay and crude oil taken from Gudao oil production plant of Shengli Oilfield in Dongying city of Shandong Province, an experiment was designed to study the characteristics and mechanism of thermal infrared emissivity spectrum of artificial crude oil slick covered seawater surface with its thickness. During the experiment, crude oil was continuously dropped into the seawater to generate artificial oil slick with different thicknesses. By adding each drop of crude oil, we measured the reflectivity of the oil slick in the thermal infrared spectrum with the Fourier transform infrared spectrometer (102F) and then calculated its thermal infrared emissivity. The results show that the thermal infrared emissivity of oil slick changes significantly with its thickness when oil slick is relatively thin (20-120 μm), which provides an effective means for detecting the existence of offshore thin oil slick In the spectrum ranges from 8 to 10 μm and from 13. 2 to 14 μm, there is a steady emissivity difference between the seawater and thin oil slick with thickness of 20 μm. The emissivity of oil slick changes marginally with oil slick thickness and

  12. Secondary electron emission characteristics of molybdenum-masked, ion-textured OFHC copper

    NASA Technical Reports Server (NTRS)

    Curren, Arthur N.; Jensen, Kenneth A.; Roman, Robert F.

    1990-01-01

    A method for producing a uniform, highly textured surface on oxygen-free, high conductivity (OFHC) copper by ion bombardment using sputtered molybdenum as a texture-inducing masking film was developed and used to provide samples for study. The purpose was to develop a basically OFHC copper surface having very low secondary electron emission characteristics. Surfaces having low secondary electron emission are a requirement for the electrodes of very high efficiency multistage depressed collectors (MDC's). Such MDC's are used in microwave amplifier traveling wave tubes for space communications and other applications. OFHC copper is the material most commonly used for MDC electrodes because it has high thermal conductivity, it is easy to machine, and its fabrication and brazing procedures are well established. However, its untreated surface displays relatively very high levels of secondary electron emissions. Textured OFHC copper samples were tested for true secondary electron emission and relative reflected primary electron yield at primary electron beam energy levels from 200 to 2000 eV and at direct (0 deg) to oblique (60 deg) beam impingement angles. The test results for three of the samples, each of which was processed in a slightly different way, are compared with each other and with test results for a machined OFHC copper sample. Although the textured samples are not represented here as having been processed optimally, their measured secondary electron emission characteristics are significantly lower than those of the untreated OFHC copper sample over the range of conditions studied. Importantly, the relative reflected primary electron yield of one of the textured samples is conspicuously lower than that of the others. Clearly, with further development, the molybdenum-masked ion-textured OFHC copper surface will be a promising material for high-efficiency MDC electrodes.

  13. Acoustic emission characteristics of copper alloys under low-cycle fatigue conditions

    NASA Technical Reports Server (NTRS)

    Krampfner, Y.; Kawamoto, A.; Ono, K.; Green, A.

    1975-01-01

    The acoustic emission (AE) characteristics of pure copper, zirconium-copper, and several copper alloys were determined to develop nondestructive evaluation schemes of thrust chambers through AE techniques. The AE counts rms voltages, frequency spectrum, and amplitude distribution analysis evaluated AE behavior under fatigue loading conditions. The results were interpreted with the evaluation of wave forms, crack propagation characteristics, as well as scanning electron fractographs of fatigue-tested samples. AE signals at the beginning of a fatigue test were produced by a sample of annealed alloys. A sample of zirconium-containing alloys annealed repeatedly after each fatigue loading cycle showed numerous surface cracks during the subsequent fatigue cycle, emitting strong-burst AE signals. Amplitude distribution analysis exhibits responses that are characteristic of certain types of AE signals.

  14. Characteristics of banded chorus-like emission measured by the TC-1 Double Star spacecraft

    NASA Astrophysics Data System (ADS)

    Macúšová, Eva; Santolík, Ondřej; Cornilleau-Wehrlin, Nicole; Yearby, Keith

    2013-04-01

    We present a study of the spatio-temporal characteristics of banded whistler-mode emissions. It covers the full operational period of the TC-1 spacecraft, between January 2004 and the end of September 2007. The analyzed data set has been visually selected from the onboard-analyzed time-frequency spectrograms of magnetic field fluctuations below 4 kHz measured by the STAFF/DWP wave instrument situated onboard the TC-1 spacecraft with a low inclination elliptical equatorial orbit. This orbit covers magnetic latitudes between -39o and 39o. The entire data set has been collected between L=2 and L=12. Our results show that almost all intense emissions (above a threshold of 10-5nT2Hz-1) occur at L-shells from 6 to 12 and in the MLT sector from 2 to 11 hours. This is in a good agreement with previous observations. We determine the bandwidth of the observed emission by an automatic procedure based on the measured spectra. This allows us to reliably calculate the integral amplitudes of the measured signals. The majority of the largest amplitudes of chorus-like emissions were found closer to the Earth. The other result is that the upper band chorus-like emissions (above one half of the electron cyclotron frequency) are much less intense than the lower band chorus-like emissions (below one half of the electron cyclotron frequency) and are usually observed closer to the Earth than the lower band. This work has received EU support through the FP7-Space grant agreement n 284520 for the MAARBLE collaborative research project.

  15. Beam impingement angle effects on secondary electron emission characteristics of textured pyrolytic graphite

    NASA Technical Reports Server (NTRS)

    Curren, A. N.; Jensen, K. A.

    1984-01-01

    Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for untreated and ion-textured pyrolytic graphite over a range of primary electron energy levels and electron beam impingement angles are presented. Information required to develop high efficiency multistage depressed collectors (MDC's) for microwave amplifier traveling-wave tubes for space communication and aircraft applications is provided. To attain the highest possible MDC efficiencies, the electrode surfaces must have low secondary electron emission characteristics. Pyrolytic graphite, a chemically vapor-deposited material, is a particularly promising candidate for this application. The pyrolytic graphite surfaces studied were tested over a range of primary electron beam energies and beam impingement angles from 200 to 2000 eV and direct (0 deg) to near-grazing angles (85 deg), respectively. Surfaces both parallel to and normal to the planes of material deposition were examined. The true secondary electron emission and reflected primary electron yield characteristics of the pyrolytic graphite surfaces are compared to those of sooted control surfaces.

  16. Characteristics of volatile organic compounds from motorcycle exhaust emission during real-world driving

    NASA Astrophysics Data System (ADS)

    Tsai, Jiun-Horng; Huang, Pei-Hsiu; Chiang, Hung-Lung

    2014-12-01

    The number of motorcycles has increased significantly in Asia, Africa, Latin American and Europe in recent years due to their reasonable price, high mobility and low fuel consumption. However, motorcycles can emit significant amounts of air pollutants; therefore, the emission characteristics of motorcycles are an important consideration for the implementation of control measures for motorcycles in urban areas. Results of this study indicate that most volatile organic compound (VOC) emission factors were in the range of several decades mg/km during on-road driving. Toluene, isopentane, 1,2,4-trimethylbenzene, m,p-xylene, and o-xylene were the most abundant VOCs in motorcycle exhaust, with emission factors of hundreds mg/km. Motorcycle exhaust was 15.4 mg/km for 15 carbonyl species. Acetaldehyde, acetone, formaldehyde and benzaldehyde were the major carbonyl species, and their emission factors ranged from 1.4 to 3.5 mg/km 1,2,4-trimethylbenzene, m,p-xylene, 1-butene, toluene, o-xylene, 1,2,3-trimethylbenzene, propene, 1,3,5-trimethylbenzene, isoprene, m-diethylbenzene, and m-ethyltoluene were the main ozone formation potential (OFP) species, and their OFP was 200 mg-O3/km or higher.

  17. Hot Gaseous Coronae around Spiral Galaxies: Probing the Illustris Simulation

    NASA Astrophysics Data System (ADS)

    Bogdán, Ákos; Vogelsberger, Mark; Kraft, Ralph P.; Hernquist, Lars; Gilfanov, Marat; Torrey, Paul; Churazov, Eugene; Genel, Shy; Forman, William R.; Murray, Stephen S.; Vikhlinin, Alexey; Jones, Christine; Böhringer, Hans

    2015-05-01

    The presence of hot gaseous coronae around present-day massive spiral galaxies is a fundamental prediction of galaxy formation models. However, our observational knowledge remains scarce, since to date only four gaseous coronae have been detected around spirals with massive stellar bodies (≳ 2× {{10}11} {{M}⊙ }). To explore the hot coronae around lower mass spiral galaxies, we utilized Chandra X-ray observations of a sample of eight normal spiral galaxies with stellar masses of (0.7-2.0)× {{10}11} {{M}⊙ }. Although statistically significant diffuse X-ray emission is not detected beyond the optical radii (˜20 kpc) of the galaxies, we derive 3σ limits on the characteristics of the coronae. These limits, complemented with previous detections of NGC 1961 and NGC 6753, are used to probe the Illustris Simulation. The observed 3σ upper limits on the X-ray luminosities and gas masses exceed or are at the upper end of the model predictions. For NGC 1961 and NGC 6753 the observed gas temperatures, metal abundances, and electron density profiles broadly agree with those predicted by Illustris. These results hint that the physics modules of Illustris are broadly consistent with the observed properties of hot coronae around spiral galaxies. However, one shortcoming of Illustris is that massive black holes, mostly residing in giant ellipticals, give rise to powerful radio-mode active galactic nucleus feedback, which results in under-luminous coronae for ellipticals.

  18. Isothermal Gaseous Detonation Model

    NASA Astrophysics Data System (ADS)

    Prokhorov, E. S.

    2015-05-01

    We propose an isothermal gaseous detonation model taking into account the initial pressure of the explosive mixture that permits describing in a simplified form both the self-sustaining and the supercompressed and undercompressed detonation regimes. The exactness of this model has been estimated on the basis of a comparative analysis with the results of equilibrium calculations of the gas-dynamic parameters at the front of detonation waves.

  19. Gaseous fuel reactor research

    NASA Technical Reports Server (NTRS)

    Thom, K.; Schneider, R. T.

    1977-01-01

    The paper reviews studies dealing with the concept of a gaseous fuel reactor and describes the structure and plans of the current NASA research program of experiments on uranium hexafluoride systems and uranium plasma systems. Results of research into the basic properties of uranium plasmas and fissioning gases are reported. The nuclear pumped laser is described, and the main results of experiments with these devices are summarized.

  20. GASEOUS DISPOSAL PROCESS

    DOEpatents

    Ryan, R.F.; Thomasson, F.R.; Hicks, J.H.

    1963-01-22

    A method is described of removing gaseous radioactive Xe and Kr from water containing O. The method consists in stripping the gases from the water stream by means of H flowing countercurrently to the stream. The gases are then heated in a deoxo bed to remove O. The carrier gas is next cooled and passed over a charcoal adsorbent bed maintained at a temperature of about --280 deg F to remove the Xe and Kr. (AEC)

  1. Gaseous diffusion system

    DOEpatents

    Garrett, George A.; Shacter, John

    1978-01-01

    1. A gaseous diffusion system comprising a plurality of diffusers connected in cascade to form a series of stages, each of said diffusers having a porous partition dividing it into a high pressure chamber and a low pressure chamber, and means for combining a portion of the enriched gas from a succeeding stage with a portion of the enriched gas from the low pressure chamber of each stage and feeding it into one extremity of the high pressure chamber thereof.

  2. Emission characteristics of carboxylates in PM2.5 from incense burning with the effect of light on acetate

    NASA Astrophysics Data System (ADS)

    Kuo, Su-Ching; Tsai, Ying I.; Sopajaree, Khajornsak

    2016-08-01

    Incense burning produces potentially harmful particulate matter. In this study we investigated the emissions of PM2.5 and gaseous acetic acid from four brands of traditional incense; Liao and Shang Lao Shan (SLS), sold in Taiwan, and Thai Yellow (Thai Y) and Thai Black (Thai B), sold in Thailand. Additionally, photochemical reactions of PM2.5 carboxylates emitted from incense burning were studied via a simulated light experiment. The average PM2.5 mass emission factor of each incense type was inversely correlated with the ash production of that incense. The Thailand incense carboxylate emissions were markedly higher than the Taiwan incense. Acetate accounted for 87.46% of total carboxylate emissions, with acetate emitted from the Thailand incense 1.26 times higher than from the Taiwan incense. Phthalate was detected in the PM2.5, indicating the presence of plasticizer. Concentrations of PM2.5 acetate, formate, pyruvate, glutarate, succinate, fumarate and tartarate were reduced in simulated light (51.5%-97.1% of those under dark), indicating that these seven types of carboxylate are easily photodegradable. In contrast, malonate, maleate, oxalate and phthalate concentrations in light were 1.17-1.84 times higher than in darkness, indicating photochemical reactions contribute to the formation of these species. The formation of the low-molecular weight dicarboxylates oxalate and malonate was most noticeable. Acetic acid, highly irritating to the respiratory system and skin, was present at high levels for all four incense types, as shown by the gaseous acetic acid/PM2.5 acetate ratios of 1.03-3.61. Burning incense indoors can generate high concentrations of PM2.5 acetate that increases the risks of respiratory and contact irritation, particularly when burning the Thailand incense. Moreover, burning incense in poorly ventilated, dimly lit indoor areas (e.g., temples and homes) can markedly increase the risk of irritation because the gaseous acetic acid is not degraded as

  3. Experimental study on the performance characteristics and emission analysis of a diesel engine using vegetable oils

    NASA Astrophysics Data System (ADS)

    Saha, Anup; Ehite, Ekramul Haque; Alam, M. M.

    2016-07-01

    In this research, Vegetable oils derived from Sesame Seed and Rice Bran were used and experimented upon. Using Kerosene as the solvent in varying proportions (30%, 50%, 70% by volume) with the vegetables oils, different blends of Sesame and Rice Bran Oils were produced. The important characteristic properties were found by experimentation and compared with those of Straight Run Diesel. Subsequently, Straight Run Diesel, vegetable oils and their blends were used to run a diesel engine one-by-one and the performance analysis was conducted, followed by an investigation of the exhaust emissions. From the comparative performance analysis, it was found that Rice Bran oil showed better performance as a fuel than Sesame with regards to power production and specific fuel consumption and also resulted in less Carbon Monoxide (CO) emission than Sesame oil blends.

  4. Frequency Characteristics of Acoustic Emission Signals from Cementitious Waste-forms with Encapsulated Al

    SciTech Connect

    Spasova, Lyubka M.; Ojovan, Michael I.

    2007-07-01

    Acoustic emission (AE) signals were continuously recorded and their intrinsic frequency characteristics examined in order to evaluate the mechanical performance of cementitious wasteform samples with encapsulated Al waste. The primary frequency in the power spectrum and its range of intensity for the detected acoustic waves were potentially related with appearance of different micro-mechanical events caused by Al corrosion within the encapsulating cement system. In addition the process of cement matrix hardening has been shown as a source of AE signals characterized with essentially higher primary frequency (above 2 MHz) compared with those due to Al corrosion development (below 40 kHz) and cement cracking (above 100 kHz). (authors)

  5. Influence of the electrode system on the emission characteristics of a vacuum spark

    SciTech Connect

    Bashutin, O. A. Alkhimova, M. A.; Vovchenko, E. D.; Dodulad, E. I.; Savelov, A. S.; Sarantsev, S. A.

    2013-11-15

    The influence of the electrode system on the emission characteristics of a high-current low-inductance vacuum spark is investigated. It is shown that the structure and composition of the spark plasma radiating in the X-ray spectral range depend substantially on the geometry and relative position of the electrodes. A mechanism related to the effect of the initial distribution of the electric field in the electrode gap is proposed to explain such a dependence. The conditions in which the radiating plasma forms from the erosion products of one or both electrodes are determined.

  6. Analysis of effect of flameholder characteristics on lean, premixed, partially vaporized fuel-air mixtures quality and nitrogen oxides emissions

    NASA Technical Reports Server (NTRS)

    Cooper, L. P.

    1981-01-01

    An analysis was conducted of the effect of flameholding devices on the precombustion fuel-air characteristics and on oxides of nitrogen (NOx) emissions for combustion of premixed partially vaporized mixtures. The analysis includes the interrelationships of flameholder droplet collection efficiency, reatomization efficiency and blockage, and the initial droplet size distribution and accounts for the contribution of droplet combustion in partially vaporized mixtures to NOx emissions. Application of the analytical procedures is illustrated and parametric predictions of NOx emissions are presented.

  7. Interpreting broad emission-line variations - II. Tensions between luminosity, characteristic size, and responsivity

    NASA Astrophysics Data System (ADS)

    Goad, M. R.; Korista, K. T.

    2015-11-01

    We investigate the variability behaviour of the broad H β emission-line to driving continuum variations in the best-studied AGN NGC 5548. For a particular choice of broad emission-line region (BLR) geometry, H β surface emissivity based on photoionization models, and using a scaled version of the 13-yr optical continuum light-curve as a proxy for the driving ionizing continuum, we explore several key factors that determine the broad emission-line luminosity L, characteristic size RRW, and variability amplitude (i.e. responsivity) η, as well as the interplay between them. For fixed boundary models which extend as far as the hot dust the predicted delays for H β are on average too long. However, the predicted variability amplitude of H β provides a remarkably good match to observations except during low-continuum states. We suggest that the continuum flux variations which drive the redistribution in H β surface emissivity F(r) do not on their own lead to large enough changes in RRW or ηeff. We thus investigate dust-bounded BLRs for which the location of the effective outer boundary is modulated by the continuum level and the dust-sublimation and dust-condensation time-scales. We find that in order to match the observed variability amplitude of broad H β in NGC 5548 a rather static outer boundary is preferred. Intriguingly, we show that the most effective way of reducing the H β delay, while preserving its responsivity and equivalent width, is to invoke a smaller value in the incident ionizing photon flux ΦH for a given ionizing source-cloud radial distance r, than is normally inferred from the observed UV continuum flux and typical models of the continuum spectral energy distribution.

  8. Fractal characteristics and acoustic emission of coal containing methane in triaxial compression failure

    NASA Astrophysics Data System (ADS)

    Kong, Xiangguo; Wang, Enyuan; Hu, Shaobin; Shen, Rongxi; Li, Xuelong; Zhan, Tangqi

    2016-01-01

    Aimed at exploring the influence of methane to coal and studying fractal characteristics and acoustic emission (AE) features in the damage evolution, the triaxial compression experiments of coal containing methane were conducted, and acoustic emission response was collected simultaneously in the loading process. Based on the method for calculating the correlation dimension, the fractal dimension was calculated with regard to time series of acoustic emission. Our experimental results indicate that AE response and fractal dimension can reflect the evolution and propagation of cracks in the loading process. Corresponding to the load-time, acoustic emission experiences active, linearly increasing, rapidly augmenting and decreasing stage. However, the fractal dimension of AE develops from chaos to orderly state. Late loading, a continued slowdown in fractal dimension, can be used as a precursory signal of coal sample destruction. In addition, the amount of gas in the coal sample will influence the evolution of pore and fracture, which causes a variation in the acoustic emission signals and fractal dimension. The maximum bearing load reduces 18.85% and 49.18% within pore pressure of 0.75 and 1.5 MPa, compared with it (24.4 kN) of the coal sample (without gas). What's more, the increase of pore pressure will cause the growth of AE count and energy, but the correlation dimension of AE parameters drops. This study is helpful for us to understand the effects of methane to coal and the evolution mechanism of cracks, and it can be applied to the research on occurrence mechanism and early warning of coal and gas outburst.

  9. Characteristics of multiple-year nitrous oxide emissions from conventional vegetable fields in southeastern China

    NASA Astrophysics Data System (ADS)

    Mei, Baoling; Zheng, Xunhua; Xie, Baohua; Dong, Haibo; Yao, Zhisheng; Liu, Chunyan; Zhou, Zaixing; Wang, Rui; Deng, Jia; Zhu, Jianguo

    2011-06-01

    The annual and interannual characteristics of nitrous oxide (N2O) emissions from conventional vegetable fields are poorly understood. We carried out 4 year measurements of N2O fluxes from a conventional vegetable cultivation area in the Yangtze River delta. Under fertilized conditions subject to farming practices, approximately 86% of the annual total N2O release occurred following fertilization events. The direct emission factors (EFd) of the 12 individual vegetable seasons investigated ranged from 0.06 to 14.20%, with a mean of 3.09% and a coefficient of variation (CV) of 142%. The annual EFd varied from 0.59 to 4.98%, with a mean of 2.88% and an interannual CV of 74%. The mean value is much larger than the latest default value (1.00%) of the Intergovernmental Panel on Climate Change. Occasional application of lagoon-stored manure slurry coupled with other nitrogen fertilizers, or basal nitrogen addition immediately followed by heavy rainfall, accounted for a substantial portion of the large EFds observed in warm seasons. The large CVs suggest that the emission factors obtained from short-term observations that poorly represent seasonality and/or interannual variability will inevitably yield large uncertainties in inventory estimation. The results of this study indicate that conventional vegetable fields associated with intensive nitrogen addition, as well as occasional applications of manure slurry, may substantially account for regional N2O emissions. However, this conclusion needs to be further confirmed through studies at multiple field sites. Moreover, further experimental studies are needed to test the mitigation options suggested by this study for N2O emissions from open vegetable fields.

  10. Effect of oxygenated fuels on physicochemical and toxicological characteristics of diesel particulate emissions.

    PubMed

    Zhang, Zhi-Hui; Balasubramanian, Rajasekhar

    2014-12-16

    A systematic study was conducted to make a comparative evaluation of the effects of blending five different oxygenates (diglyme (DGM), palm oil methyl ester (PME), dimethyl carbonate (DMC), diethyl adipate (DEA), and butanol (Bu)) with ultralow sulfur diesel (ULSD) at 2% and 4% oxygen levels on physicochemical and toxicological characteristics of particulate emissions from a nonroad diesel engine. All blended fuels led to an overall decrease in the particulate mass concentration and elemental carbon (EC) emissions, which was strongly associated with the oxygen content in fuels and the specific type of fuels used. In general, the proportion of particulate-bound organic carbon (OC) and water-soluble organic carbon (WSOC) increased while using oxygenated fuel blends. Compared to ULSD, all fuel blends showed different emission factors of particle-phase PAHs and n-alkanes, slight alterations in soot nanostructure, lower soot ignition temperature, and lower activation energy. The total counts of particles (≤ 560 nm diameter) emitted decreased gradually for ULSD blended with DMC, DEA, and Bu, while they increased significantly for other fuel blends. The in vitro toxicity of particulates significantly increased with ULSD blended with DMC and DEA, while it decreased when ULSD was blended with PME, DGM, and Bu. PMID:25383974

  11. [Emission characteristics of PM10 from coal-fired industrial boiler].

    PubMed

    Li, Chao; Li, Xing-Hua; Duan, Lei; Zhao, Meng; Duan, Jing-Chun; Hao, Ji-Ming

    2009-03-15

    Through ELPI (electrical low-pressure impactor) based dilution sampling system, the emission characteristics of PM10 and PM2.5 was studied experimentally at the inlet and outlet of dust catchers at eight different coal-fired industrial boilers. Results showed that a peak existed at around 0.12-0.20 microm of particle size for both number size distribution and mass size distribution of PM10 emitted from most of the boilers. Chemical composition analysis indicated that PM2.5 was largely composed of organic carbon, elementary carbon, and sulfate, with mass fraction of 3.7%-21.4%, 4.2%-24.6%, and 1.5%-55.2% respectively. Emission factors of PM10 and PM2.5 measured were 0.13-0.65 kg x t(-1) and 0.08-0.49 kg x t(-1) respectively for grate boiler using raw coal, and 0.24 kg x t(-1) and 0.22 kg x t(-1) for chain-grate boiler using briquette. In comparison, the PM2.5 emission factor of fluidized bed boiler is 1.14 kg x t(-1), much her than that of grate boiler. Due to high coal consumption and low efficiency of dust separator, coal-fired industrial boiler may become the most important source of PM10, and should be preferentially controlled in China. PMID:19432307

  12. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    SciTech Connect

    Venkattraman, Ayyaswamy

    2013-11-15

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission.

  13. Evaluating the Field Emission Characteristics of Aluminum for DC High Voltage Photo-Electron Guns

    NASA Astrophysics Data System (ADS)

    Taus, Rhys; Poelker, Matthew; Forman, Eric; Mamun, Abdullah

    2014-03-01

    High current photoguns require high power laser light, but only a small portion of the laser light illuminating the photocathode produces electron beam. Most of the laser light (~ 65%) simply serves to heat the photocathode, which leads to evaporation of the chemicals required to create the negative electron affinity condition necessary for photoemission. Photocathode cooling techniques have been employed to address this problem, but active cooling of the photocathode is complicated because the cooling apparatus must float at high voltage. This work evaluates the field emission characteristics of cathode electrodes manufactured from materials with high thermal conductivity: aluminum and copper. These electrodes could serve as effective heat sinks, to passively cool the photocathode that resides within such a structure. However, literature suggests ``soft'' materials like aluminum and copper are ill suited for photogun applications, due to excessive field emission when biased at high voltage. This work provides an evaluation of aluminum and copper electrodes inside a high voltage field emission test stand, before and after coating with titanium nitride (TiN), a coating that enhances surface hardness. National Science Foundation Award Number: 1062320 and the Department of Defence ASSURE program.

  14. Emission Characteristics of High Color Rendering Index Low-Pressure Xe and CO ICP's Light Source

    NASA Astrophysics Data System (ADS)

    Nazri, Ahmad; Kondo, Akira; Motomura, Hideki; Jinno, Masafumi

    High color rendering index (CRI) has been obtained from mercury-free ICP’s lamp. Due to the strong demand on the development of mercury-free light sources, the authors investigated xenon and CO as an alternative element. These rare (Xe) and molecule (CO) gases have been used as a substitute for mercury as the environmental problems related necessitate the development of new type of light sources. The target of this study is to develop a new type of mercury-free lamp without using a phosphor where the authors concentrate on how to obtain a strong visible light instead of UV. In this paper, the colors, luminance and emission characteristics of these types of mercury-free ICP’s lamp is discussed. Without the use of phosphor, the authors obtained a good color rendering from xenon and CO ICP’s lamp where their CRI’s above 90. A strong continuum emission in visible region is obtained where luminance are ranged from 2000 to 25000 cd/m2 at 100 W of input power. Spectral distribution shows the continuum emissions are similar to the daylight distribution and chromaticity diagrams shows they are close to white region in color coordinates and color temperatures bringing a high index of the lamp’s color rendering.

  15. Characteristics of wall sheath and secondary electron emission under different electron temperature in Hall thruster

    NASA Astrophysics Data System (ADS)

    Duan, Ping; Qin, Haijuan; Cao, Anning; Zhou, Xinwei; Chen, Long; Gao, Hong

    2013-09-01

    Characteristics of discharge channel wall plasma sheath in Hall thruster have great effects on its performance. In this paper, we establish a two-dimensional physical model in Hall thruster sheath area to investigate the influences of the different electron temperature, propellant and particle weight on sheath potential and secondary electron emission in Hall thruster, by the method of Particle In Cell (PIC) simulation. And the electric field at the particle position is obtained by solving the Poisson's equation. The numerical results show that when the electron temperature is low, the change of sheath potential drop is bigger than that with electrons at high temperature, the surface potential maintains a stable value and the stability of the sheath is good. When the electron temperature is high, the surface potential maintains persistent oscillation, and the stability of the sheath is reduced. Along with the increase of electron temperature, the coefficient of secondary electron emission in wall reduce after the first increasing. For three kinds of propellant (Ar, Kr, Xe), with the increase of ion mass, sheath potential and the secondary electron emission coefficient in turn reduce.

  16. Characteristics of dioxins and metals emission from radwaste plasma arc melter system.

    PubMed

    Yang, Hee-Chul; Kim, Joon-Hyung

    2004-11-01

    This study investigated the emission characteristics of PCDD/Fs and the partitioning of three heavy metals (Cd, Hg and Pb) and two radioactive metal surrogates (Co and Cs) in a radwaste plasma arc melter system. Typical mixtures of low-level radioactive wastes were simulated as the trial burn surrogate wastes. The emission of PCDD/Fs and the partitioning of the metals were strongly influenced by the feed waste stream and melter operating temperature, respectively. The emissions of PCDD/Fs, cadmium and lead were greatly enhanced when the polyvinyl chloride was included in the feed waste stream. Most of the nonvolatile cobalt partitioned into the glass. A significant quantity of cesium, cadmium and lead was vaporized during the highest melter temperature test. A lower melter temperature resulted in more cesium, cadmium and lead species remaining in the glass. The results of this study suggest that wet scrubbing as well as a low-temperature two-step fine filtration, or both of them together could not effectively capture the gas-phase or fine particle phase PCDD/Fs and mercury species. In order to effectively treat low-level radioactive waste streams, the tested high-temperature melter should include an adsorption system, which could collect the gas-phase PCDD/Fs and mercury species. PMID:15331269

  17. [Nitrogen removal and N2O emission characteristics during the shortcut simultaneous nitrification and denitrification process].

    PubMed

    Liang, Xiao-ling; Li, Ping; Wu, Jin-hua; Wang, Xiang-de

    2013-05-01

    Complete simultaneous nitrification and denitrification (SND) was achieved in an air lift circulation bioreactor. Based on this condition, the system could be switched to shortcut SND as the free ammonia (FA) concentration was increased with higher influent pH. The nitrogen removal and N2O emission characteristics of the shortcut SND process were investigated and those of the complete SND process were also observed as control. In the shortcut SND process, the average total nitrogen removal and average SND efficiency reached 71.9% and 80.9%, which was 18.0 and 16.8 percents higher than those in the complete SND process, respectively. In addition, the total nitrogen removal rate in the shortcut SND process was 0.11 mg x (L x min)(-1), 1.4 times as high as that in the complete SND process. Although higher nitrogen removal efficiency was obtained in the shortcut SND process, the mean N2O conversion rate reached 57.1% and the average N2O accumulated emission amount was approximately 4 times higher than that in the complete SND process. The results also indicated that the increase of NO2- -N concentration in the reactor should be responsible for the remarkable enhancement of N2O emission. PMID:23914537

  18. Comparative analysis of scintillation characteristics derived from different emission mechanisms in BaCl2

    NASA Astrophysics Data System (ADS)

    Fukabori, Akihiro

    2015-04-01

    Crack-free La3+-substituted BaCl2 single crystals without and with Eu2+ as an activator were successfully grown using the micro-pulling-down method. Luminescence bands from BaCl2 without and with the Eu2+ activator were assigned as mainly intrinsic and extrinsic, respectively. Therefore, BaCl2 as a host material is suitable for investigating the effects of the emission mechanism on the non-proportionality curves and energy resolution plots. First, the scintillation characteristics of BaCl2:La3+(11 at. %) and BaCl2:La3+(7.7 at. %):Eu2+(0.5 at. %) single crystals were determined along with those of BaCl2 and BaCl2:Eu2+(0.5 at. %) crystals. Second, the non-proportionality curves from the different emission origins in BaCl2 were confirmed to be consistent with phenomenological models. Third, the non-proportionality curves and energy resolution plots originating from intrinsic (without Eu2+) and extrinsic (with Eu2+) luminescence were compared. The results experimentally demonstrated that the emission mechanism influenced scintillator non-proportionality curves.

  19. Redox-responsive nanoparticles with Aggregation-Induced Emission (AIE) characteristic for fluorescence imaging.

    PubMed

    Cheng, Weiren; Wang, Guan; Pan, Xiaoyong; Zhang, Yong; Tang, Ben Zhong; Liu, Ye

    2014-08-01

    The redox environment between intracellular compartments and extracellular matrix is significantly different, and the cellular redox homeostasis determines many physiological functions. Here, redox-responsive nanoparticles with aggregation-induced emission (AIE) characteristic for fluorescence imaging are developed by encapsulation of fluorophore with redox "turn-on" AIE characteristic, TPE-MI, into the micelles of poly(ethylene glycol) (PEG)- and cholesterol (CE)-conjugated disulfide containing poly(amido amine)s. The redox-responsive fluorescence profiles of the nanoparticles are investigated after reaction with glutathione (GSH). The encapsulation of TPE-MI in micelles leads to a higher efficiency and red shift in emission, and the fluorescence intensity of the nanoparticles increases with the concentration of GSH. Confocal microscopy imaging shows that the nanoparticles can provide obvious contrast between the intracellular compartments and the extracellular matrix in MCF-7 and HepG2 cells. So the nanoparticles with PEG shells and low cytotoxicity are promising to provide fluorescence bioimaging with a high contrast and for differentiation of cellular redox environment. PMID:24771703

  20. [Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

    PubMed

    Cao, Na; Wang, Rui; Liao, Ting-ting; Chen, Nuo; Zheng, Xun-hua; Yao, Zhi-sheng; Zhang, Hai; Butterbach-Bahl, Klaus

    2015-09-01

    Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields. The initial concentrations of soil nitrate and dissolved organic carbon (DOC) were set at approximately 50 mg.kg-1 and mg.kg-1, respectively, by adding a mixture solution of KNO3 and glucose. The emissions of N2, N2O NO, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each soil sample were measured simultaneously, using a gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that the accumulative emissions of N2, N2O and NO of the two soil samples for the entire incubation period were 6 - 8, 20, and 15 - 18 mg.kg-1, respectively. By measuring the cumulative emissions of denitrification gases (N, = N2 + N2O + NO) we were able to explain 95% to 98% of observed changes in s1ifr nilrate concentrations. The mass fractions of N2, N2O and NO emissions to Nt were approximately 15% -19%, 47% -49%, and 34% -36%, respectively. Thus, in our experiments N2O and NO were the main products of denitrification for the entire incubation period. However, as the temporal courses of hourly or daily production of the denitrification gases showed, NO production dominated and peaked firstly, and then N2O, before finally N2 became the dominant product. Our results show the high temporal dynamic of

  1. Gaseous Fuel Injection Modeling using a Gaseous Sphere Injection Methodology

    SciTech Connect

    Hessel, R P; Aceves, S M; Flowers, D L

    2006-03-06

    The growing interest in gaseous fuels (hydrogen and natural gas) for internal combustion engines calls for the development of computer models for simulation of gaseous fuel injection, air entrainment and the ensuing combustion. This paper introduces a new method for modeling the injection and air entrainment processes for gaseous fuels. The model uses a gaseous sphere injection methodology, similar to liquid droplet in injection techniques used for liquid fuel injection. In this paper, the model concept is introduced and model results are compared with correctly- and under-expanded experimental data.

  2. Characteristics of On-road Diesel Vehicles: Black Carbon Emissions in Chinese Cities Based on Portable Emissions Measurement.

    PubMed

    Zheng, Xuan; Wu, Ye; Jiang, Jingkun; Zhang, Shaojun; Liu, Huan; Song, Shaojie; Li, Zhenhua; Fan, Xiaoxiao; Fu, Lixin; Hao, Jiming

    2015-11-17

    Black carbon (BC) emissions from heavy-duty diesel vehicles (HDDVs) are rarely continuously measured using portable emission measurement systems (PEMSs). In this study, we utilize a PEMS to obtain real-world BC emission profiles for 25 HDDVs in China. The average fuel-based BC emissions of HDDVs certified according to Euro II, III, IV, and V standards are 2224 ± 251, 612 ± 740, 453 ± 584, and 152 ± 3 mg kg(-1), respectively. Notably, HDDVs adopting mechanical pump engines had significantly higher BC emissions than those equipped with electronic injection engines. Applying the useful features of PEMSs, we can relate instantaneous BC emissions to driving conditions using an operating mode binning methodology, and the average emission rates for Euro II to Euro IV diesel trucks can be constructed. From a macroscopic perspective, we observe that average speed is a significant factor affecting BC emissions and is well correlated with distance-based emissions (R(2) = 0.71). Therefore, the average fuel-based and distance-based BC emissions on congested roads are 40 and 125% higher than those on freeways. These results should be taken into consideration in future emission inventory studies. PMID:26462141

  3. A numerical study comparing the combustion and emission characteristics of biodiesel with petrodiesel.

    SciTech Connect

    Som, S.; Longman, D.

    2011-04-01

    Combustion and emission characteristics of compression ignition engines strongly depend upon inner-nozzle flow and spray behavior. These processes control the fuel-air mixing, which in turn is critical for the combustion process. Previous studies by us highlighted the differences in the physical and chemical properties of petrodiesel and biodiesel, which significantly altered the inner-nozzle flow and spray structure. The current study is another step in this direction to gain a fundamental understanding on the influence of fuel properties on the combustion and emission characteristics of the compression ignition engine. n-Heptane and methyl butanoate were selected as surrogates for diesel and biodiesel fuels, respectively, because the chemical kinetic pathways were well-understood. Liquid length and flame lift-off length for diesel and biodiesel fuels were validated against data available in the literature. Liquid lengths were always higher for biodiesel because of its higher heat of vaporization, which resulted in increased interplay between spray and combustion processes under all conditions investigated. Ambient air entrainment was also lower for biodiesel mainly because of slower atomization and breakup. The mechanism for flame stabilization is further analyzed by estimating the turbulent burning velocity for both of the fuels. This analysis revealed that neither flame propagation nor isolated ignition kernels upstream and detached from high-temperature regions can be the mechanism for flame stabilization. Flame propagation speeds were observed to be similar for both fuels. Biodiesel predicted lower soot concentrations, which were also reflected in reduced C{sub 2}H{sub 2} mole fractions. Although prompt NO{sub x} was higher for biodiesel, total NO{sub x} was lower because of reduced thermal NO{sub x}. The ignition delay and NO{sub x} emissions predicted by these simulations do not agree with trends reported in the literature; hence, this study highlights the

  4. Emissions and Characteristics of Ice Nucleating Particles Associated with Laboratory Generated Nascent Sea Spray Aerosol

    NASA Astrophysics Data System (ADS)

    McCluskey, C. S.; Hill, T. C. J.; Beall, C.; Sultana, C. M.; Moore, K.; Cornwell, G.; Lee, C.; Al-Mashat, H.; Laskina, O.; Trueblood, J.; Grassian, V. H.; Prather, K. A.; Kreidenweis, S. M.; DeMott, P. J.

    2015-12-01

    Accurate emission rates and activity spectra of atmospheric ice nucleating particles (INPs) are required for proper representation of aerosol-cloud interactions in atmospheric modeling studies. However, few investigations have quantified or characterized oceanic INP emissions. In conjunction with the Center for Aerosol Impacts on the Climate and the Environment, we have directly measured changes in INP emissions and properties of INPs from nascent sea spray aerosol (SSA) through the evolution of phytoplankton blooms. Multiple offline and online instruments were used to monitor aerosol chemistry and size, and bulk water characteristics during two phytoplankton bloom experiments. Two methods were utilized to monitor the number concentrations of INPs from 0 to -34 °C: The online CSU continuous flow diffusion chamber (CFDC) and collections processed offline using the CSU ice spectrometer. Single particle analyses were performed on ice crystal residuals downstream of the CFDC, presumed to be INPs, via scanning transmission electron microscopy (STEM) and Raman microspectroscopy. Preliminary results indicate that laboratory-generated nascent SSA corresponds to number concentrations of INPs that are generally consistent with open ocean regions, based on current knowledge. STEM analyses revealed that the sizes of ice crystal residuals that were associated with nascent SSA ranged from 0.3 to 2.5 μm. Raman microspectroscopy analysis of 1 μm sized residuals found a variety of INP identities, including long chain organics, diatom fragments and polysaccharides. Our data suggest that biological processes play a significant role in ocean INP emissions by generating the species and compounds that were identified during these studies.

  5. Development of Functional Nanomaterials with Aggregation-Induced Emission Characteristics and Exploration of Their Biological Applications

    NASA Astrophysics Data System (ADS)

    Hong, Yuning

    2011-12-01

    The development of fluorescent biosensors with high sensitivity, selectivity, and biocompatibility is of critical importance to bioscience and biotechnology because it offers a direct visualization tool for the detection of biological macromolecules and the monitoring of biological events under real and living conditions. Most of the conventional organic fluorophores exhibit remarkably bright emission in their dilute solutions but become weakly or even nonemissive when aggregated or in solid state, which has greatly limited the scope of their applications. An opposite phenomenon has recently been discovered: a group of nonluminescent molecules are induced to emit efficiently by aggregate formation. "Aggregation-induced emission" (AIE) is coined for this novel effect. Attracted by the intriguing phenomenon and its fascinating perspectives, we have launched a new program directed towards the development of new AIE materials and exploration of their biological applications. A new class of water-soluble AIE luminogens are designed and synthesized. Hydrophilic groups such as hydroxyl, sulfonate, and amino groups are introduced to make the AIE molecules readily soluble in water. Being practically non-emissive in water, these AIE dyes are lightened up when bound to biomacromolecules, such as proteins and DNA, thus enabling the quantitation and visualization of biomacromolecules in aqueous solutions and in electrophoretic gels. The AIE luminogens are sensitive to microenvironment inside the biomolecules and their fluorescent intensity can readily reflect the global stability of the biomolecules. In this work, we employ the AIE luminogens as fluorescent reporters for the monitoring of G-quadruplex DNA folding, protein unfolding by denaturant and protein misfolding into amyloid fibrils. Thanks to the AIE characteristics, the delicate information on the conformational transition of the biomolecules can be revealed. In addition, lipophilic AIE luminogens form highly emissive

  6. Correlating Well-Pad Characteristics and Methane Emissions in the Marcellus Shale

    NASA Astrophysics Data System (ADS)

    Lu, J.; Caulton, D.; Lane, H.; Stanton, L. G.; Zondlo, M. A.

    2015-12-01

    Methane leaks from petrochemical activity are significant contributors to the total amount of methane in the atmosphere. While natural gas has been praised as a cleaner source of fuel than coal, methane's potent global-warming potential could pose barriers in reducing greenhouse gas footprints if significant leaks are observed from the natural gas supply chain. A field campaign spanning two and a half weeks was undertaken in July 2015 to quantify the levels of methane emitted from sites of petrochemical activity in the Marcellus Shale. Additional campaigns are expected in late 2015 and early 2016. Measurements of methane and carbon dioxide were taken downwind of known well sites using open-path laser spectroscopy mounted to the roof of the mobile platform. Approximately 250 well sites were visited, covering over 2000 miles on the road. The majority of the well pads were in southwestern Pennsylvania, but the compiled database includes wells in West Virginia and northeastern Pennsylvania. The data set consists of a variety of operators and equipment types spread over several counties. Correlating well pad characteristics with emission levels may provide useful insight into predicting which well pads are likely to be large emitters. Using the inverse Gaussian plume model and meteorology data from the NOAA Ready archive, the emissions from each transect were calculated. Preliminary results were examined with respect to two easily identifiable variables: the number of wells at each well pad and the operator. Higher emissions were not correlated with increased number of wells, despite the fact that additional infrastructure may provide additional leak pathways. In fact, the emission levels for pads with only a singular well, which accounted for nearly 70% of the wells analyzed thus far, had a range of 0 to 9 grams of methane per second. Sites with two or more wells tended to be concentrated on the lower end of the distribution. Higher emissions were also distributed

  7. Trapping behavior of gaseous cesium by fly ash filters.

    PubMed

    Shin, J M; Park, J J; Song, K C; Kim, J H

    2009-01-01

    The high volatility of a gaseous form and its high chemical reactivity make a cesium emission control very difficult work. In this study, fly ash filters were tested for the removal of gaseous cesium from a hot flue gas under air and hydrogen conditions at 700-1000 degrees C. Tests were performed by using a simulated gaseous cesium volatilized from Cs(2)SiO(3) in a two-zone furnace. Fly ash filter was found to be the most promising filter for trapping the gaseous cesium. The results of the trapping tests are presented, along with the effects of the temperature, superficial gas velocity, and carrier gas on the cesium trapping quantity. PMID:19375925

  8. Field Emission Characteristics of the Structure of Vertically Aligned Carbon Nanotube Bundles.

    PubMed

    Lin, Pao-Hung; Sie, Cong-Lin; Chen, Ching-An; Chang, Hsuan-Chen; Shih, Yi-Ting; Chang, Hsin-Yueh; Su, Wei-Jhih; Lee, Kuei-Yi

    2015-12-01

    In this study, we performed thermal chemical vapor deposition for growing vertically aligned carbon nanotube (VACNT) bundles for a field emitter and applied photolithography for defining the arrangement pattern to simultaneously compare square and hexagonal arrangements by using two ratios of the interbundle distance to the bundle height (R) of field emitters. The hexagon arrangement with R = 2 had the lowest turn-on electric field (E to) and highest enhancement factor, whereas the square arrangement with R = 3 had the most stable field emission (FE) characteristic. The number density can reveal the correlation to the lowest E to and highest enhancement factor more effectively than can the R or L. The fluorescent images of the synthesized VACNT bundles manifested the uniformity of FE currents. The results of our study indicate the feasibility of applying the VACNT field emitter arrangement to achieve optimal FE performance. PMID:26183388

  9. Acoustic emission characteristics of subsoil subjected to vertical pile loading in sand

    NASA Astrophysics Data System (ADS)

    Mao, Wuwei; Aoyama, Shogo; Goto, Shigeru; Towhata, Ikuo

    2015-08-01

    The response of the subsoil subjected to pile loading is crucial to clarify the bearing mechanism of pile foundations. This study presents a novel acoustic emission (AE) method to monitor the subsoil behavior in a model pile testing system. The AE testing aims to capture the "micro-noises" released from sand grain dislocation and crushing around the pile shaft during penetration. The correlations between the pile settlement and the AE characteristics including count, amplitude and energy are revealed and discussed, highlighting that the ground density and the shear zone formed during pile penetration mainly affect the AE behavior. The results also suggest that the yielding of ground can be determined based on the development of the AE activity. The technique shows promise as an in-situ methodology for monitoring of subsoil behavior during the process of pile loading.

  10. Experimental study on combustion characteristics and NOX emissions of pulverized anthracite preheated by circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhu, Jian-Guo; Lu, Qing-Gang

    2011-08-01

    A 30 kW bench-scale rig of pulverized anthracite combustion preheated by a circulating fluidized bed (CFB) was developed. The CFB riser has a diameter of 90 mm and a height of 1,500 mm. The down-fired combustion chamber (DFCC) has a diameter of 260 mm and a height of 3,000 mm. Combustion experiments were carried out using pulverized anthracite with 6.74% volatile content. This low volatile coal is difficult to ignite and burn out. Therefore, it requires longer burnout time and higher combustion temperature, which results in larger NOX emissions. In the current study, important factors that influence the combustion characteristics and NOX emissions were investigated such as excess air ratio, air ratio in the reducing zone, and fuel residence time in the reducing zone. Pulverized anthracite can be quickly preheated up to 800°C in CFB when the primary air is 24% of theoretical air for combustion, and the temperature profile is uniform in DFCC. The combustion efficiency is 94.2%, which is competitive with other anthracite combustion technologies. When the excess air ratio ranges from 1.26 to 1.67, the coal-N conversion ratio is less than 32% and the NOX emission concentration is less than 371 mg/m3 (@6% O2). When the air ratio in the reducing zone is 0.12, the NOX concentration is 221 mg/m3 (@6% O2), and the coal-N conversion ratio is 21%, which is much lower than that of other boilers.

  11. Investigation on emission characteristics of metal-ceramic cathode applied to industrial X-ray diode.

    PubMed

    Xun, Ma; Jianqiang, Yuan; Hongwei, Liu; Hongtao, Li; Lingyun, Wang; Ping, Jiang

    2016-06-01

    The industrial x-ray diode with high impedance configuration is usually adopted to generate repetitive x-ray, but its performance would be worsened due to lower electric field on the cathode of diode when a voltage of several hundreds of kV is applied. To improve its performance, a novel metal-ceramic cathode is proposed in this paper. Key factors (width, relative permittivity of ceramic, and so on) affecting electric field distribution on triple points are analyzed by electrostatic field calculation program, so as to optimize the design of this novel cathode. Experiments are done to study the characteristics including emission current of cathode, diode voltage duration, diode mean dynamic impedance, and diode impedance drop velocity within diode power duration. The results show that metal-ceramic cathode could improve diode performance by enhancing emission current and stabling impedance; the impedance drop velocity of diode with spoke-shaped metal-ceramic cathode was reduced to -5 Ω ns(-1) within diode power duration, comparing to -15 Ω ns(-1) with metal foil cathode. PMID:27370441

  12. Investigation on emission characteristics of metal-ceramic cathode applied to industrial X-ray diode

    NASA Astrophysics Data System (ADS)

    Xun, Ma; Jianqiang, Yuan; Hongwei, Liu; Hongtao, Li; Lingyun, Wang; Ping, Jiang

    2016-06-01

    The industrial x-ray diode with high impedance configuration is usually adopted to generate repetitive x-ray, but its performance would be worsened due to lower electric field on the cathode of diode when a voltage of several hundreds of kV is applied. To improve its performance, a novel metal-ceramic cathode is proposed in this paper. Key factors (width, relative permittivity of ceramic, and so on) affecting electric field distribution on triple points are analyzed by electrostatic field calculation program, so as to optimize the design of this novel cathode. Experiments are done to study the characteristics including emission current of cathode, diode voltage duration, diode mean dynamic impedance, and diode impedance drop velocity within diode power duration. The results show that metal-ceramic cathode could improve diode performance by enhancing emission current and stabling impedance; the impedance drop velocity of diode with spoke-shaped metal-ceramic cathode was reduced to -5 Ω ns-1 within diode power duration, comparing to -15 Ω ns-1 with metal foil cathode.

  13. Influence of emissive layer thickness on electrical characteristics of polyfluorene copolymer based polymer light emitting diodes

    NASA Astrophysics Data System (ADS)

    Das, D.; Gopikrishna, P.; Singh, A.; Dey, A.; Iyer, P. K.

    2016-04-01

    Polymer light emitting diodes (PLEDs) with a device configuration of ITO/PEDOT:PSS/PFONPN01 [Poly [2,7-(9,9’-dioctylfluorene)-co-N-phenyl-1,8-naphthalimide (99:01)]/LiF/Al have been fabricated by varying the emissive layer (EML) thickness (40/65/80/130 nm) and the influence of EML thickness on the electrical characteristics of PLED has been studied. PLED can be modelled as a simple combination of resistors and capacitors. The impedance spectroscopy analysis showed that the devices with different EML thickness had different values of parallel resistance (RP) and the parallel capacitance (CP). The impedance of the devices is found to increase with increasing EML thickness resulting in an increase in the driving voltage. The device with an emissive layer thickness of 80nm, spin coated from a solution of concentration 15 mg/mL is found to give the best device performance with a maximum brightness value of 5226 cd/m2.

  14. Neutron Emission Characteristics of Two Mixed-Oxide Fuels: Simulations and Initial Experiments

    SciTech Connect

    D. L. Chichester; S. A. Pozzi; J. L. Dolan; M. Flaska; J. T. Johnson; E. H. Seabury; E. M. Gantz

    2009-07-01

    Simulations and experiments have been carried out to investigate the neutron emission characteristics of two mixed-oxide (MOX) fuels at Idaho National Laboratory (INL). These activities are part of a project studying advanced instrumentation techniques in support of the U.S. Department of Energy's Fuel Cycle Research and Development program and it's Materials Protection, Accounting, and Control for Transmutation (MPACT) campaign. This analysis used the MCNP-PoliMi Monte Carlo simulation tool to determine the relative strength and energy spectra of the different neutron source terms within these fuels, and then used this data to simulate the detection and measurement of these emissions using an array of liquid scintillator neutron spectrometers. These calculations accounted for neutrons generated from the spontaneous fission of the actinides in the MOX fuel as well as neutrons created via (alpha,n) reactions with oxygen in the MOX fuel. The analysis was carried out to allow for characterization of both neutron energy as well as neutron coincidences between multiple detectors. Coincidences between prompt gamma rays and neutrons were also analyzed. Experiments were performed at INL with the same materials used in the simulations to benchmark and begin validation tests of the simulations. Data was collected in these experiments using an array of four liquid scintillators and a high-speed waveform digitizer. Advanced digital pulse-shape discrimination algorithms were developed and used to collect this data. Results of the simulation and modeling studies are presented together with preliminary results from the experimental campaign.

  15. Japan's research on gaseous flames

    NASA Technical Reports Server (NTRS)

    Niioka, Takashi

    1995-01-01

    Although research studies on gaseous flames in microgravity in Japan have not been one-sided, they have been limited, for the most part, to comparatively fundamental studies. At present it is only possible to achieve a microgravity field by the use of drop towers, as far as gaseous flames are concerned. Compared with experiments on droplets, including droplet arrays, which have been vigorously performed in Japan, studies on gaseous flames have just begun. Experiments on ignition of gaseous fuel, flammability limits, flame stability, effect of magnetic field on flames, and carbon formation from gaseous flames are currently being carried out in microgravity. Seven subjects related to these topics are introduced and discussed herein.

  16. [Characteristic of Mercury Emissions and Mass Balance of the Typical Iron and Steel Industry].

    PubMed

    Zhang, Ya-hui; Zhang, Cheng; Wang, Ding-yong; Luo, Cheng-zhong; Yang, Xi; Xu, Feng

    2015-12-01

    To preliminarily discuss the mercury emission characteristics and its mass balance in each process of the iron and steel production, a typical iron and steel enterprise was chosen to study the total mercury in all employed materials and estimate the input and output of mercury during the steel production process. The results showed that the mercury concentrations of input materials in each technology ranged 2.93-159.11 µg · kg⁻¹ with the highest level observed in ore used in blast furnace, followed by coal of sintering and blast furnace. The mercury concentrations of output materials ranged 3.09-18.13 µg · kg⁻¹ and the mercury concentration of dust was the highest, followed by converter slag. The mercury input and the output in the coking plant were 1346.74 g · d⁻¹ ± 36.95 g · d⁻¹ and 177.42 g · d⁻¹ ± 13.73 g · d⁻¹, respectively. In coking process, mercury mainly came from the burning of coking coal. The sintering process was the biggest contributor for mercury input during the iron and steel production with the mercury input of 1075. 27 g · d⁻¹ ± 60.89 g · d⁻¹ accounting for 68.06% of the total mercury input during this production process, and the ore powder was considered as the main mercury source. For the solid output material, the output in the sintering process was 14.15 g · d⁻¹ ± 0.38 g · d⁻¹, accounting for 22.61% of the total solid output. The mercury emission amount from this studied iron and steel enterprise was estimated to be 553.83 kg in 2013 with the emission factor of 0.092 g · t⁻¹ steel production. Thus, to control the mercury emissions, iron and steel enterprises should combine with production practice, further reduce energy consumption of coking and sintering, or improve the quality of raw materials and reduce the input of mercury. PMID:27011969

  17. VOC characteristics, emissions and contributions to SOA formation during hazy episodes

    NASA Astrophysics Data System (ADS)

    Sun, Jie; Wu, Fangkun; Hu, Bo; Tang, Guiqian; Zhang, Junke; Wang, Yuesi

    2016-09-01

    Volatile organic compounds (VOC) are important precursors of secondary organic aerosols (SOA). The pollution processes in Beijing were investigated from 18th October to 6th November 2013 to study the characteristics, SOA formation potential and contributing factors of VOC during hazy episodes. The mean concentrations of VOC were 67.4 ± 33.3 μg m-3 on clear days and have 5-7-fold increase in polluted periods. VOC concentrations rapidly increased at a visibility range of 4-5 km with the rate of 25%/km in alkanes, alkenes and halocarbons and the rate of 45%/km in aromatics. Analysis of the mixing layer height (MLH); wind speed and ratios of benzene/toluene (B/T), ethylbenzene/m,p-xylene (E/X), and isopentane/n-pentane (i/n) under different visibility conditions revealed that the MLH and wind speed were the 2 major factors affecting the variability of VOC during clear days and that local emissions and photochemical reactions were main causes of VOC variation on polluted days. Combined with the fractional aerosol coefficient (FAC) method, the SOA formation potentials of alkanes, alkenes and aromatics were 0.3 ± 0.2 μg m-3, 1.1 ± 1.0 μg m-3 and 6.5 ± 6.4 μg m-3, respectively. As the visibility deteriorated, the SOA formation potential increased from 2.1 μg m-3 to 13.2 μg m-3, and the fraction of SOA-forming aromatics rapidly increased from 56.3% to 90.1%. Initial sources were resolved by a positive matrix factorization (PMF) model. Vehicle-related emissions were an important source of VOC at all visibility ranges, accounting for 23%-32%. As visibility declined, emissions from solvents and the chemical industry increased from 13.2% and 6.3% to 34.2% and 23.0%, respectively. Solvents had the greatest SOA formation ability, accounting for 52.5% on average on hazy days, followed by vehicle-related emissions (20.7%).

  18. Effects of Al interlayer coating and thermal treatment on electron emission characteristics of carbon nanotubes deposited by electrophoretic method

    PubMed Central

    2014-01-01

    The effects of aluminum (Al) interlayer coating and thermal post-treatment on the electron emission characteristics of carbon nanotubes (CNTs) were investigated. These CNTs were deposited on conical-shaped tungsten (W) substrates using an electrophoretic method. The Al interlayers were coated on the W substrates via magnetron sputtering prior to the deposition of CNTs. Compared with the as-deposited CNTs, the thermally treated CNTs revealed significantly improved electron emission characteristics, such as the decrease of turn-on electric fields and the increase of emission currents. The observations of Raman spectra confirmed that the improved emission characteristics of the thermally treated CNTs were ascribed to their enhanced crystal qualities. The coating of Al interlayers played a role in enhancing the long-term emission stabilities of the CNTs. The thermally treated CNTs with Al interlayers sustained stable emission currents without any significant degradation even after continuous operation of 20 h. The X-ray photoelectron spectroscopy (XPS) study suggested that the cohesive forces between the CNTs and the underlying substrates were strengthened by the coating of Al interlayers. PMID:24959105

  19. A study on methane and nitrous oxide emissions characteristics from anthracite circulating fluidized bed power plant in Korea.

    PubMed

    Lee, Seehyung; Kim, Jinsu; Lee, Jeongwoo; Jeon, Eui-Chan

    2012-01-01

    In order to tackle climate change effectively, the greenhouse gas emissions produced in Korea should be assessed precisely. To do so, the nation needs to accumulate country-specific data reflecting the specific circumstances surrounding Korea's emissions. This paper analyzed element contents of domestic anthracite, calorific value, and concentration of methane (CH₄) and nitrous oxide (N₂O) in the exhaust gases from circulating fluidized bed plant. The findings showed the concentration of CH₄ and N₂O in the flue gas to be 1.85 and 3.25 ppm, respectively, and emission factors were 0.486 and 2.198 kg/TJ, respectively. The CH₄ emission factor in this paper was 52% lower than default emission factor presented by the IPCC. The N₂O emission factor was estimated to be 46% higher than default emission factor presented by the IPCC. This discrepancy can be attributable to the different methods and conditions of combustion because the default emission factors suggested by IPCC take only fuel characteristics into consideration without combustion technologies. Therefore, Korea needs to facilitate research on a legion of fuel and energy consumption facilities to develop country-specific emission factors so that the nation can have a competitive edge in the international climate change convention in the years to come. PMID:22666126

  20. A Study on Methane and Nitrous Oxide Emissions Characteristics from Anthracite Circulating Fluidized Bed Power Plant in Korea

    PubMed Central

    Lee, Seehyung; Kim, Jinsu; Lee, Jeongwoo; Jeon, Eui-Chan

    2012-01-01

    In order to tackle climate change effectively, the greenhouse gas emissions produced in Korea should be assessed precisely. To do so, the nation needs to accumulate country-specific data reflecting the specific circumstances surrounding Korea's emissions. This paper analyzed element contents of domestic anthracite, calorific value, and concentration of methane (CH4) and nitrous oxide (N2O) in the exhaust gases from circulating fluidized bed plant. The findings showed the concentration of CH4 and N2O in the flue gas to be 1.85 and 3.25 ppm, respectively, and emission factors were 0.486 and 2.198 kg/TJ, respectively. The CH4 emission factor in this paper was 52% lower than default emission factor presented by the IPCC. The N2O emission factor was estimated to be 46% higher than default emission factor presented by the IPCC. This discrepancy can be attributable to the different methods and conditions of combustion because the default emission factors suggested by IPCC take only fuel characteristics into consideration without combustion technologies. Therefore, Korea needs to facilitate research on a legion of fuel and energy consumption facilities to develop country-specific emission factors so that the nation can have a competitive edge in the international climate change convention in the years to come. PMID:22666126

  1. Environmental monitoring report: United States Department of Energy, Paducah Gaseous Diffusion Plant, calendar year 1983

    SciTech Connect

    Not Available

    1984-05-01

    Air, water, soil, sediments, grass, and groundwater in the vicinity of the Paducah Gaseous Diffusion Plant were continuously or periodically sampled during 1983. Analyses for materials known to be in plant effluents were made to provide effluent control information and to determine compliance with applicable environmental standards. Low sulfur coal is burned in the steam plant to meet Kentucky emission limits for sulfur dioxide. Air analyses for radioactivity indicated concentrations at each offsite sampling station averaged less than 1% of the applicable Radioactivity Concentration Guide. Offsite analyses for fluorides in grass met the Kentucky Air Quality Requirements. All onsite and offsite airborne fluoride samples met the Kentucky one-week and one-month standards for gaseous HF. Soil samples were analyzed for uranium and showed no significant deviation from normal background concentrations. There was no detectable change in chemical, physical, or radioactive characteristics of either the Ohio River or ground water attributable to Paducah Gaseous Diffusion Plant operations. The results of water sample analyses of the Ohio River show the chromium and fluoride concentrations to be in compliance with the requirements of the applicable Kentucky regulations. Algal activity resulted in an increase in pH violations during 1983. 7 references, 7 figures, 26 tables.

  2. United States Department of Energy Paducah Gaseous Diffusion Plant. Environmental monitoring report, calendar year 1984

    SciTech Connect

    Not Available

    1985-07-01

    Air, water, soil, sediments, grass, and groundwater in the vicinity of the Paducah Gaseous Diffusion Plant were continuously or periodically sampled during 1984. Analyses for materials known to be in plant effluents were made to provide effluent control information and to determine compliance with applicable environmental standards. Low sulfur coal is burned in the steam plant to meet Kentucky emission limits for sulfur dioxide. Air analyses for radioactivity indicated concentrations at each off-site sampling station averaged less than 1% of the DOE Radioactivity Concentration Guide (RCG). Offsite analyses for fluorides in grass met the Kentucky Air Quality Requirements. All onsite and offsite airborne fluoride samples met the Kentucky one-week and one-month standards for gaseous HF. Soil samples were analyzed for uranium and showed no significant deviation from normal background concentrations. There was no detectable change in chemical, physical, or radioactive characteristics of the Ohio River attributable to Paducah Gaseous Diffusion Plant operations. The results of water sample analyses of the Ohio River show the chromium and fluoride concentrations to be in compliance with the requirements of the applicable Kentucky regulations. 7 figs., 26 tabs.

  3. 40 CFR 91.414 - Raw gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Raw gaseous exhaust sampling and analytical system description. 91.414 Section 91.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.414...

  4. An overview of key emissions sources and ambient pollution characteristics from major cities in North America

    NASA Astrophysics Data System (ADS)

    Herndon, Scott; Fortner, Edward; Knighton, Berk; Floerchinger, Cody; Yacovitch, Tara; Roscioli, Rob; Zahniser, Mark; Nelson, David; Kolb, Charles; Zavala, Miguel; Molina, Luisa

    2013-04-01

    Many urban anthropogenic emission sources are difficult to characterize. They can be distributed across a spatial scale that precludes specific vector sampling. Others are difficult to identify a specific point of emissions. Novel emissions quantification methods, including fuel-based emission indicies and tracer flux ratio, are described and evaluated for a variety of urban pollution sources. These techniques can be used to quantify emissions for a large range of species including methane and carbon dioxide isotopes, formaldehyde and other toxic volatile organic carbon compounds, nitrogen oxides, carbon monoxide and black carbon particulate matter. Results from urban emissions source case-studies using a mobile laboratory either alone or in conjunction with tracer-release will be described. These include on road light duty and heavy duty vehicle emissions, in-use aircraft engine emissions at airports, and industrial emission sources.

  5. CO 2-laser photoacoustic detection of gaseous n-pentylacetate

    NASA Astrophysics Data System (ADS)

    Herecová, Lenka; Hejzlar, Tomáš; Pavlovský, Jiří; Míček, Dalibor; Zelinger, Zdeněk; Kubát, Pavel; Janečková, Radmila; Nevrlý, Václav; Bitala, Petr; Střižík, Michal; Klouda, Karel; Civiš, Svatopluk

    2009-07-01

    The absorption spectra of gaseous n-pentylacetate were investigated by FT IR spectroscopy as well as CO 2-laser photoacoustic spectroscopy for simulation of the dispersion of a nerve agent (sarin) within a modeled atmospheric boundary layer. Three CO 2-laser emission lines were used for photoacoustic detection of n-pentylacetate with detection limit in the range of 1-3 ppm.

  6. Effects of particulate oxidation catalyst on unregulated pollutant emission and toxicity characteristics from heavy-duty diesel engine.

    PubMed

    Feng, Xiangyu; Ge, Yunshan; Ma, Chaochen; Tan, Jianwei

    2015-01-01

    To evaluate the effects of particulate oxidation catalyst (POC) on unregulated pollutant emission and toxicity characteristics, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), soot, soluble organic fractions (SOF) and sulphate emissions emitted from a heavy-duty diesel engine retrofitted with a POC were investigated on a diesel bench. The particulate matter (PM) in the exhaust was collected by Teflon membrane, and the PAHs and VOCs were analysed by a gas chromatography/mass spectrometer (GC/MS). The results indicate that the POC exhibits good performance on the emission control of VOCs, PAHs and PM. The POC and the diesel particulate filters (DPF) both show a good performance on reducing the VOCs emission. Though the brake-specific emission (BSE) reductions of the total PAHs by the POC were lower than those by the DPF, the POC still removed almost more than 50% of the total PAHs emission. After the engine was retrofitted with the POC, the reductions of the PM mass, SOF and soot emissions were 45.2-89.0%, 7.8-97.7% and 41.7-93.3%, respectively. The sulphate emissions decreased at low and medium loads, whereas at high load, the results were contrary. The PAHs emissions were decreased by 32.4-69.1%, and the contributions of the PAH compounds were affected by the POC, as well as by load level. The benzo[a]pyrene equivalent (BaPeq) of PAHs emissions were reduced by 35.9-97.6% with the POC. The VOCs emissions were reduced by 21.8-94.1% with the POC, and the reduction was more evident under high load. PMID:25424012

  7. Feasibility of gas-phase decontamination of gaseous diffusion equipment

    SciTech Connect

    Munday, E.B.; Simmons, D.W.

    1993-02-01

    The five buildings at the K-25 Site formerly involved in the gaseous diffusion process contain 5000 gaseous diffusion stages as well as support facilities that are internally contaminated with uranium deposits. The gaseous diffusion facilities located at the Portsmouth Gaseous Diffusion Plant and the Paducah Gaseous Diffusion Plant also contain similar equipment and will eventually close. The decontamination of these facilities will require the most cost-effective technology consistent with the criticality, health physics, industrial hygiene, and environmental concerns; the technology must keep exposures to hazardous substances to levels as low as reasonably achievable (ALARA). This report documents recent laboratory experiments that were conducted to determine the feasibility of gas-phase decontamination of the internal surfaces of the gaseous diffusion equipment that is contaminated with uranium deposits. A gaseous fluorinating agent is used to fluorinate the solid uranium deposits to gaseous uranium hexafluoride (UF{sub 6}), which can be recovered by chemical trapping or freezing. The lab results regarding the feasibility of the gas-phase process are encouraging. These results especially showed promise for a novel decontamination approach called the long-term, low-temperature (LTLT) process. In the LTLT process: The equipment is rendered leak tight, evacuated, leak tested, and pretreated, charged with chlorine trifluoride (ClF{sub 3}) to subatmospheric pressure, left for an extended period, possibly > 4 months, while processing other items. Then the UF{sub 6} and other gases are evacuated. The UF{sub 6} is recovered by chemical trapping. The lab results demonstrated that ClF{sub 3} gas at subatmospheric pressure and at {approx} 75{degree}F is capable of volatilizing heavy deposits of uranyl fluoride from copper metal surfaces sufficiently that the remaining radioactive emissions are below limits.

  8. Emission Characteristics of Organic Light-Emitting Diodes and Organic Thin-Films with Planar and Corrugated Structures

    PubMed Central

    Wei, Mao-Kuo; Lin, Chii-Wann; Yang, Chih-Chung; Kiang, Yean-Woei; Lee, Jiun-Haw; Lin, Hoang-Yan

    2010-01-01

    In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs) and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design of microcavity structure and layer thicknesses adjustment, optical characteristics can be engineered to achieve high optical intensity, suitable emission wavelength, and broad viewing angles. To increase the extraction efficiency from OLEDs and organic thin-films, corrugated structure with micro- and nano-scale were applied. Microstructures can effectively redirects the waveguiding light in the substrate outside the device. For nanostructures, it is also possible to couple out the organic and plasmonic modes, not only the substrate mode. PMID:20480033

  9. A study on emission characteristics of an EFI engine with ethanol blended gasoline fuels

    NASA Astrophysics Data System (ADS)

    He, Bang-Quan; Wang, Jian-Xin; Hao, Ji-Ming; Yan, Xiao-Guang; Xiao, Jian-Hua

    The effect of ethanol blended gasoline fuels on emissions and catalyst conversion efficiencies was investigated in a spark ignition engine with an electronic fuel injection (EFI) system. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and changes distillation temperature. Ethanol can decrease engine-out regulated emissions. The fuel containing 30% ethanol by volume can drastically reduce engine-out total hydrocarbon emissions (THC) at operating conditions and engine-out THC, CO and NO x emissions at idle speed, but unburned ethanol and acetaldehyde emissions increase. Pt/Rh based three-way catalysts are effective in reducing acetaldehyde emissions, but the conversion of unburned ethanol is low. Tailpipe emissions of THC, CO and NO x have close relation to engine-out emissions, catalyst conversion efficiency, engine's speed and load, air/fuel equivalence ratio. Moreover, the blended fuels can decrease brake specific energy consumption.

  10. Optical emission characteristics of surface nanosecond pulsed dielectric barrier discharge plasma

    SciTech Connect

    Wu Yun; Li Yinghong; Jia Min; Song Huimin; Liang Hua

    2013-01-21

    This paper reports an experimental study of the optical emission characteristics of the surface dielectric barrier discharge plasma excited by nanosecond pulsed voltage. N{sub 2}(C{sup 3}{Pi}{sub u}) rotational and vibrational temperatures are almost the same with upper electrode powered with positive polarity and lower electrode grounded or upper electrode grounded and lower electrode powered with positive polarity. While the electron temperature is 12% higher with upper electrode powered with positive polarity and lower electrode grounded. When the frequency is below 2000 Hz, there is almost no influence of applied voltage amplitude and frequency on N{sub 2}(C{sup 3}{Pi}{sub u}) rotational, vibrational temperature and electron temperature. As the pressure decreases from 760 Torr to 5 Torr, N{sub 2}(C{sup 3}{Pi}{sub u}) rotational temperature remains almost unchanged, while its vibrational temperature decreases initially and then increases. The discharge mode changes from a filamentary type to a glow type around 80 Torr. In the filamentary mode, the electron temperature remains almost unchanged. In the glow mode, the electron temperature increases while the pressure decreases.

  11. Room temperature-synthesized vertically aligned InSb nanowires: electrical transport and field emission characteristics

    PubMed Central

    2013-01-01

    Vertically aligned single-crystal InSb nanowires were synthesized via the electrochemical method at room temperature. The characteristics of Fourier transform infrared spectrum revealed that in the syntheses of InSb nanowires, energy bandgap shifts towards the short wavelength with the occurrence of an electron accumulation layer. The current–voltage curve, based on the metal–semiconductor–metal model, showed a high electron carrier concentration of 2.0 × 1017 cm−3 and a high electron mobility of 446.42 cm2 V−1 s−1. Additionally, the high carrier concentration of the InSb semiconductor with the surface accumulation layer induced a downward band bending effect that reduces the electron tunneling barrier. Consequently, the InSb nanowires exhibit significant field emission properties with an extremely low turn-on field of 1.84 V μm−1 and an estimative threshold field of 3.36 V μm−1. PMID:23399075

  12. Convenient, Rapid and Accurate Measurement of SVOC Emission Characteristics in Experimental Chambers

    PubMed Central

    Liu, Cong; Liu, Zhe; Little, John C.; Zhang, Yinping

    2013-01-01

    Chamber tests are usually used to determine the source characteristics of semi-volatile organic compounds (SVOCs) which are critical to quantify indoor exposure to SVOCs. In contrast to volatile organic compounds (VOCs), the sorption effect of SVOCs to chamber surfaces usually needs to be considered due to the much higher surface/air partition coefficients, resulting in a long time to reach steady state, frequently on the order of months, and complicating the mathematical analysis of the resulting data. A chamber test is also complicated if the material-phase concentration is not constant. This study shows how to design a chamber to overcome these limitations. A dimensionless mass transfer analysis is used to specify conditions for (1) neglecting the SVOC sorption effect to chamber surfaces, (2) neglecting the convective mass transfer resistance at sorption surfaces if the sorption effect cannot be neglected, and (3) regarding the material-phase concentration in the source as constant. Several practical and quantifiable ways to improve chamber design are proposed. The approach is illustrated by analyzing available data from three different chambers in terms of the accuracy with which the model parameters can be determined and the time needed to conduct the chamber test. The results should greatly facilitate the design of chambers to characterize SVOC emissions and the resulting exposure. PMID:24015246

  13. [Emission characteristics and safety evaluation of volatile organic compounds in manufacturing processes of automotive coatings].

    PubMed

    Zeng, Pei-Yuan; Li, Jian-Jun; Liao, Dong-Qi; Tu, Xiang; Xu, Mei-Ying; Sun, Guo-Ping

    2013-12-01

    Emission characteristics of volatile organic compounds (VOCs) were investigated in an automotive coating manufacturing enterprise. Air samples were taken from eight different manufacturing areas in three workshops, and the species of VOCs and their concentrations were measured by gas chromatography-mass spectrometry (GC-MS). Safety evaluation was also conducted by comparing the concentration of VOCs with the permissible concentration-short term exposure limit (PC-STEL) regulated by the Ministry of Health. The results showed that fifteen VOCs were detected in the indoor air of the automotive coatings workshop, including benzene, toluene, ethylbenzene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, trimethylbenzene and ethylene glycol monobutyl ether, Their concentrations widely ranged from 0.51 to 593.14 mg x m(-3). The concentrations of TVOCs were significantly different among different manufacturing processes. Even in the same manufacturing process, the concentrations of each component measured at different times were also greatly different. The predominant VOCs of indoor air in the workshop were identified to be ethylbenzene and butyl acetate. The concentrations of most VOCs exceeded the occupational exposure limits, so the corresponding control measures should be taken to protect the health of the workers. PMID:24640895

  14. Molecular Structure of Photosynthetic Microbial Biofuels for Improved Engine Combustion and Emissions Characteristics

    PubMed Central

    Hellier, Paul; Purton, Saul; Ladommatos, Nicos

    2015-01-01

    The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes. PMID:25941673

  15. Molecular structure of photosynthetic microbial biofuels for improved engine combustion and emissions characteristics.

    PubMed

    Hellier, Paul; Purton, Saul; Ladommatos, Nicos

    2015-01-01

    The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes. PMID:25941673

  16. Dynamic secondary electron emission characteristics of polymers in negative charging process

    NASA Astrophysics Data System (ADS)

    Weng, Ming; Hu, Tian-Cun; Zhang, Na; Cao, Meng

    2016-04-01

    We studied the dynamic secondary electron emission (SEE) characteristics of a polyimide sample in negative charging process under electron bombardment. The time evolution of secondary electron yield (SEY) has been measured with a pulsed electron gun. The dynamic SEY, as well as the surface potential have been analyzed using a capacitance model. The shift in surface potential caused by the negative charge accumulation on the sample reduces the landing energy of the primary electrons (PEs), which in turn alters the SEY. The charging process tends to be stable when the landing energy of PEs reaches the secondary crossover energy where the corresponding SEY is 1. The surface potential has an approximately negative exponential relationship with the irradiation time. The total accumulated charge at the stable state is found to be proportional to the product of the sample capacitance and the difference between initial incident energy and the secondary crossover energy. The time constant of the exponential function is proportional to the ratio of final accumulated charge to the incident current.

  17. Characterization of helium/argon working gas systems in a radiofrequency glow discharge atomic emission source. Part I: Optical emission, sputtering and electrical characteristics

    NASA Astrophysics Data System (ADS)

    Christopher, Steven J.; Hartenstein, Matthew L.; Marcus, R. Kenneth; Belkin, Mikhail; Caruso, Joseph A.

    1998-08-01

    Studies are performed to determine the influence of discharge gas composition (helium/argon working gas mixtures) on the analyte emission signal intensities, sputtering rates, and DC-bias characteristics of an analytical radiofrequency glow discharge atomic emission spectroscopy (RF-GD-AES) source. As the partial pressure of He is increased from 0 to 15 torr, increased emission intensity is observed for a range of bulk and trace elements in NIST 1250 SRM (low alloy steel), regardless of the base pressure of Ar in the source (5 and 9 torr). In contrast to increases in analyte emission intensity of up to 300%, counterindicative decreases in the sputtering rates on the order of about 30-50% are observed. The magnitude of these effects depends on both the partial pressure of helium introduced to the source and the total pressure of the He and Ar gases. Use of relative emission yield (REY) to normalize changes in emission intensity to sputtering rates indicates that excitation efficiencies increase under these conditions. Increases in average electron energy and temperature appear to control this response. Decreases in both analyte emission intensities and sputter rates occur with increasing He partial pressure when the total pressure in the cell remains fixed (11 torr in these studies). Emission yields for the fixed pressure, mixed gas plasmas decrease as the partial pressure of He (He/Ar ratio) in the RF-GD source increases. In this case, decreases in electron number densities appear to dictate the lower REYs. Measurement of DC-bias values at the sample surface provide understanding with respect to the observed changes in sputtering rates as well as suggest the origins of changes in plasma electron energetics. Use of a diamond stylus profilometer provides both the quantitative sputter rate information as well as qualitative insights into the use of mixed gas plasmas for enhanced depth profiling capabilities. The analyte emission characteristics of these mixed gas

  18. Characteristics of x-ray emission from optically thin high-Z plasmas in the soft x-ray region

    NASA Astrophysics Data System (ADS)

    Ohashi, Hayato; Higashiguchi, Takeshi; Suzuki, Yuhei; Arai, Goki; Li, Bowen; Dunne, Padraig; O'Sullivan, Gerry; Sakaue, Hiroyuki A.; Kato, Daiji; Murakami, Izumi; Tamura, Naoki; Sudo, Shigeru; Koike, Fumihiro; Suzuki, Chihiro

    2015-07-01

    The characteristics of soft x-ray emission from optically thin high-Z plasmas of gold, lead and bismuth were investigated with the large helical device. Compared to optically thicker laser-produced plasmas, significantly different spectral structures were observed due to the difference in opacities and electron temperatures. Peak structures appearing in unresolved transition arrays were identified by calculations using atomic structure codes. The main contributors of discrete line emission in each case were Pd-, Ag-, and Rh-like ion stages. The present calculations point to the overestimation of contributions for 4p-4d transitions based on intensity estimates arising purely from gA distributions that predict strong emission from 4p-4d transitions. Understanding of such spectral emission is not only important for the completion of databases of high-Z highly ion charge states but also the development of promising high brightness sources for biological imaging applications.

  19. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

    PubMed Central

    Karthikeya Sharma, T.

    2014-01-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied. PMID:26644918

  20. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

    PubMed

    Karthikeya Sharma, T

    2015-11-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied. PMID:26644918

  1. Long-Term Formaldehyde Emissions from Medium-Density Fiberboard in a Full-Scale Experimental Room: Emission Characteristics and the Effects of Temperature and Humidity.

    PubMed

    Liang, Weihui; Yang, Shen; Yang, Xudong

    2015-09-01

    We studied formaldehyde emissions from the medium-density fiberboard (MDF) in a full-scale experimental room to approximate emissions in actual buildings. Detailed indoor formaldehyde concentrations and temperature and humidity data were obtained for about 29 months. Temperature, relative humidity (RH), and absolute humidity (AH) ranged over -10.9-31.4 °C, 46.5-83.6%, and 1.1-23.1 g/kgair, respectively. Annual cyclical seasonal variations were observed for indoor formaldehyde concentrations and emission rates, exhibiting entirely different characteristics than those in an environmental chamber under constant environmental conditions. The maximum concentration occurred in summer rather than at initial introduction of the material. The concentrations in summer could be a few up to 20 times higher than that in winter, depending on the indoor temperature and humidity conditions. Concentrations decreased by 20-65% in corresponding months of the second year. Indoor formaldehyde concentrations were positively correlated with temperature and AH but were poorly correlated with RH. The combined effects of temperature and AH on formaldehyde emissions from MDF in actual buildings were verified. These detailed long-term experimental results could be used with environmental chamber measurement data to scale up and validate emission models from chambers held at constant conditions to actual buildings. PMID:26263171

  2. Gas concentration measurement instrument based on the effects of a wave-mixing interference on stimulated emissions

    DOEpatents

    Garrett, W. Ray

    1997-01-01

    A method and apparatus for measuring partial pressures of gaseous components within a mixture. The apparatus comprises generally at least one tunable laser source, a beam splitter, mirrors, optical filter, an optical spectrometer, and a data recorder. Measured in the forward direction along the path of the laser, the intensity of the emission spectra of the gaseous component, at wavelengths characteristic of the gas component being measured, are suppressed. Measured in the backward direction, the peak intensities characteristic of a given gaseous component will be wavelength shifted. These effects on peak intensity wavelengths are linearly dependent on the partial pressure of the compound being measured, but independent of the partial pressures of other gases which are present within the sample. The method and apparatus allow for efficient measurement of gaseous components.

  3. Gas concentration measurement instrument based on the effects of a wave-mixing interference on stimulated emissions

    DOEpatents

    Garrett, W.R.

    1997-11-11

    A method and apparatus are disclosed for measuring partial pressures of gaseous components within a mixture. The apparatus comprises generally at least one tunable laser source, a beam splitter, mirrors, optical filter, an optical spectrometer, and a data recorder. Measured in the forward direction along the path of the laser, the intensity of the emission spectra of the gaseous component, at wavelengths characteristic of the gas component being measured, are suppressed. Measured in the backward direction, the peak intensities characteristic of a given gaseous component will be wavelength shifted. These effects on peak intensity wavelengths are linearly dependent on the partial pressure of the compound being measured, but independent of the partial pressures of other gases which are present within the sample. The method and apparatus allow for efficient measurement of gaseous components. 9 figs.

  4. [Study of the microwave emissivity characteristics of vegetation over the Northern Hemisphere].

    PubMed

    Shi, Li-Juan; Qiu, Yu-Bao; Shi, Jian-Cheng

    2013-05-01

    The microwave emissivity is a function of structure, water content, and surface roughness, and all these factors have obvious seasonal variations. In the present study, the half-month averaged emissivities in summer and winter of 2003 over the vegetation of Northern Hemisphere were estimated using Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) combined with IGBP (International Geosphere-Biosphere Project labels) land classification data. Then the emissivities of vegetation land covers at different frequencies, the polarization and their seasonal variations were analyzed respectively. The results show that the emissivities of vegetation increase with the increase in frequencies, and decline with the frequency increasing over snow region. In summer, the vegetation emissivity at V-polarization of 89 GHz is larger than 0.944, and all emissivities are relatively stable and the RMSE of time series emissivity variation is less than 0.007 2. In winter, emissivities decrease over snow covered area, especially for higher frequencies. Furthermore, with the increase in vegetation density, the emissivities increase and emissivity polarization difference decreases. PMID:23905309

  5. Effects of methanol-containing additive on emission characteristics from a heavy-duty diesel engine.

    PubMed

    Chao, M R; Lin, T C; Chao, H R; Chang, F H; Chen, C B

    2001-11-12

    This study was aimed to investigate the effect of methanol-containing additive (MCA) on the regulated emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), as well as the unregulated carbon dioxide (CO2) and polycyclic aromatic hydrocarbons (PAHs) from a diesel engine. The engine was tested on a series of diesel fuels blended with five additive levels (0, 5, 8, 10 and 15% of MCA by volume). Emissions tests were performed under both cold- and hot-start transient heavy-duty federal test procedure (HD-FTP) cycles and two selected steady-state modes. Results show that MCA addition slightly decreases PM emissions but generally increases both THC and CO emissions. Decrease in NOx emissions was found common in all MCA blends. As for unregulated emissions, CO2 emissions did not change significantly for all MCA blends, while vapor-phase and particle-associated PAHs emissions in high load and transient cycle tests were relatively low compared to the base diesel when either 5 or 8% MCA was used. This may be attributed to the lower PAHs levels in MCA blends. Finally, the particle-associated PAHs emissions also showed trends quite similar to that of the PM emissions in this study. PMID:11712594

  6. Angular ion emission characteristics of a laser triggered tin vacuum arc as light source for extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Verbraak, Harald; Küpper, Felix; Jonkers, Jeroen; Bergmann, Klaus

    2010-11-01

    The angular resolved emission of tin ions from a laser triggered vacuum arc to be used as light source for extreme ultraviolet lithography is presented. Ion energies of more than 200 keV for emission angles up to 50° with respect to the optical axis are observed. The angular emission characteristic is strongly anisotropic with a pronounced peak for fast ions into a cone with an opening angle of roughly 10° at an angle of 35° with respect to the optical axis. These ions also exhibit a distinct energy distribution function compared to the more isotropic emitted bulk of ions, which can be referred to different mechanisms of production. Looking at the discharge current parameters, the production of the directed fast ions can be connected with a peaked increase in the impedance, which gives hint to a plasma instability as origin of those ions. The emission of isotropic emitted ions is in agreement with a model of plasma expansion into vacuum. The emission characteristic is also strongly dependent on the parameter of the trigger laser. It is shown that using a double trigger laser pulse the fast ion production can be suppressed by more than one order of magnitude.

  7. Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes.

    PubMed

    Liu, Huan; Luo, Guang-Qian; Hu, Hong-Yun; Zhang, Qiang; Yang, Jia-Kuan; Yao, Hong

    2012-10-15

    Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH(3)), sulfur dioxide (SO(2)), hydrogen sulfide (H(2)S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO(2) and H(2)S emissions in the H(2)SO(4) conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant release of NH(3). PMID:22902143

  8. Effect of substrate material on the growth and field emission characteristics of large-area carbon nanotube forests

    NASA Astrophysics Data System (ADS)

    Ummethala, Raghunandan; Wenger, Daniela; Tedde, Sandro F.; Täschner, Christine; Leonhardt, Albrecht; Büchner, Bernd; Eckert, Jürgen

    2016-01-01

    Carbon nanotubes (CNTs) are a promising replacement for tungsten filaments as electron emitters in conventional x-ray sources, owing to their higher aspect ratio, superior mechanical stability, chemical inertness, and high electrical and thermal conductivities. Conditions for realizing the best emission behavior from CNTs have been formulated over the last few years. In this paper, we report the relatively less-investigated factor, namely, the influence of the nature of substrate material on the growth as well as field emission characteristics of large-area multiwalled CNTs for their practical application in medical x-ray sources. We compare the morphology of CNTs on a variety of substrates such as stainless steel, copper, molybdenum, graphite, few-layer graphene, and carbon nanowalls grown by thermal chemical vapor deposition following a simple drop-coating of catalyst. We find that CNTs grown on stainless steel and graphite show the best combination of emission characteristics under pulsed operation mode. These studies are helpful in selecting the optimum substrate material for field emission applications. Ex situ studies on field emission degradation of CNTs are presented towards the end.

  9. Temporal trends and spatial variation characteristics of primary air pollutants emissions from coal-fired industrial boilers in Beijing, China.

    PubMed

    Xue, Yifeng; Tian, Hezhong; Yan, Jing; Zhou, Zhen; Wang, Junling; Nie, Lei; Pan, Tao; Zhou, Junrui; Hua, Shenbing; Wang, Yong; Wu, Xiaoqing

    2016-06-01

    Coal-fired combustion is recognized as a significant anthropogenic source of atmospheric compounds in Beijing, causing heavy air pollution events and associated deterioration in visibility. Obtaining an accurate understanding of the temporal trends and spatial variation characteristics of emissions from coal-fired industrial combustion is essential for predicting air quality changes and evaluating the effectiveness of current control measures. In this study, an integrated emission inventory of primary air pollutants emitted from coal-fired industrial boilers in Beijing is developed for the period of 2007-2013 using a technology-based approach. Future emission trends are projected through 2030 based on current energy-related and emission control policies. Our analysis shows that there is a general downward trend in primary air pollutants emissions because of the implementation of stricter local emission standards and the promotion by the Beijing municipal government of converting from coal-fired industrial boilers to gas-fired boilers. However, the ratio of coal consumed by industrial boilers to total coal consumption has been increasing, raising concerns about the further improvement of air quality in Beijing. Our estimates indicate that the total emissions of PM10, PM2.5, SO2, NOx, CO and VOCs from coal-fired industrial boilers in Beijing in 2013 are approximately 19,242 t, 13,345 t, 26,615 t, 22,965 t, 63,779 t and 1406 t, respectively. Under the current environmental policies and relevant energy savings and emission control plans, it may be possible to reduce NOx and other air pollutant emissions by 94% and 90% by 2030, respectively, if advanced flue gas purification technologies are implemented and coal is replaced with natural gas in the majority of existing boilers. PMID:27023281

  10. Effects of dietary ingredients on manure characteristics and odorous emissions from swine.

    PubMed

    Gralapp, A K; Powers, W J; Faust, M A; Bundy, D S

    2002-06-01

    Two feeding studies were conducted to examine the impact of dietary inclusion of specific feed ingredients on manure characteristics and manure odor. In one study, 72 finishing pigs were used to evaluate the effects of distillers dried grains with solubles (DDGS) on pig performance, manure characteristics, and odorous emissions. Three diets containing 0, 5, and 10% DDGS were fed during six 4-wk feeding periods. Week 1 served as a dietary adjustment period. Animals were housed in two feeding rooms (six pigs/room) with one treatment/room. A new group of animals (average initial BW = 85.8 kg) was used for each feeding period. Diets were replicated four times. Rooms were equipped with individual shallow manure storage pits that were cleaned once weekly (d 7). On d 4 and 7 of each week, manure pit samples, for chemical analyses, and air samples, for olfactometry analysis, were collected from each room. Odor dilution threshold was greater on d 7 than on d 4 of manure storage across all treatments (P < 0.01). No treatment differences in manure composition were noted. In the second study, weaned pigs (approximately 5 wk old) were fed isonitrogenous diets containing 0, 1.5, or 3% bloodmeal. Pigs were housed by diet (three pigs/diet) in one of four individual feeding rooms. A new group of pigs was used for each of the two, 4-wk feeding periods. During period 1, the 3% bloodmeal diet was fed in two of the four rooms; the 0% bloodmeal diet was fed in two rooms during period 2. Manure samples, for chemical analyses, and air samples, for olfactometry analysis, were collected 2 d per week (d 4 and d 6) from each room during wk 2 through 4. No significant treatment differences were observed for odor dilution threshold (P = 0.30). Longer manure storage time, 6 d vs 4 d, resulted in a larger odor dilution ratio (P < 0.01). Manure composition was unaltered by storage time. Results suggest that odor intensifies during storage. PMID:12078731

  11. Ambient air quality and emission characteristics in and around a non-recovery type coke oven using high sulphur coal.

    PubMed

    Saikia, Jyotilima; Saikia, Prasenjit; Boruah, Ratan; Saikia, Binoy K

    2015-10-15

    The objective of this study is to determine the concentrations of gaseous species and aerosols in and around a non-recovery type coke making oven using high sulphur coals. In this paper, physico-chemical properties of the feed coal sample are reported along with the collection and measurement of the emitted gases (SO2, NO2, and NH3) and aerosol particles (PM2.5, PM10) during the coal carbonization in the oven. The coals used are from northeast India and they are high sulphur in nature. The concentrations of the gases e.g., SO2, NO2 and NH3 emitted are observed to be within the limit of National Ambient Air Quality Standard for 24h. The mean PM10 and PM2.5 concentrations are found to be 125.4 μg/m(3) and 48.6 μg/m(3) respectively, as measured during three days of coke oven operations. About 99% of the SO2 in flue gases is captured by using an alkali treatment during the coke oven operation. A Principal Component Analysis (PCA) after Centred Log Ratio (clr) transformation is also performed to know the positive and negative correlation among the coal properties and the emission parameters. PMID:26047865

  12. Bridging aero-fracture evolution with the characteristics of the acoustic emissions in a porous medium

    NASA Astrophysics Data System (ADS)

    Turkaya, Semih; Toussaint, Renaud; Eriksen, Fredrik; Zecevic, Megan; Daniel, Guillaume; Flekkøy, Eirik; Måløy, Knut Jørgen

    2015-09-01

    The characterization and understanding of rock deformation processes due to fluid flow is a challenging problem with numerous applications. The signature of this problem can be found in Earth Science and Physics, notably with applications in natural hazard understanding, mitigation or forecast (e.g. earthquakes, landslides with hydrological control, volcanic eruptions), or in industrial applications such as hydraulic-fracturing, steam-assisted gravity drainage, CO sequestration operations or soil remediation. Here we investigate the link between the visual deformation and the mechanical wave signals generated due to fluid injection into porous media. In a rectangular Hele-Shaw Cell, side air injection causes burst movement and compaction of grains along with channeling (creation of high permeability channels empty of grains). During the initial compaction and emergence of the main channel, the hydraulic fracturing in the medium generates a large non-impulsive low frequency signal in the frequency range 100 Hz - 10 kHz. When the channel network is established, the relaxation of the surrounding medium causes impulsive aftershock-like events, with high frequency (above 10 kHz) acoustic emissions, the rate of which follows an Omori Law. These signals and observations are comparable to seismicity induced by fluid injection. Compared to the data obtained during hydraulic fracturing operations, low frequency seismicity with evolving spectral characteristics have also been observed. An Omori-like decay of microearthquake rates is also often observed after injection shut-in, with a similar exponent p≃0.5 as observed here, where the decay rate of aftershock follows a scaling law dN/dt ∝(t-t₀ )-p . The physical basis for this modified Omori law is explained by pore pressure diffusion affecting the stress relaxation.

  13. Characteristics of polycyclic aromatic hydrocarbons and their gas/particle partitioning from fugitive emissions in coke plants

    NASA Astrophysics Data System (ADS)

    Mu, Ling; Peng, Lin; Liu, Xiaofeng; Song, Chongfang; Bai, Huiling; Zhang, Jianqiang; Hu, Dongmei; He, Qiusheng; Li, Fan

    2014-02-01

    Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. However, there is little information available on the emission characteristics of PAHs from fugitive emission during coking, especially on the specific processes dominating the gas-particle partitioning of PAHs. In this study, emission characteristics and gas-particle partitioning of PAHs from fugitive emission in four typical coke plants (CPs) with different scales and techniques were investigated. The average concentrations of total PAHs from fugitive emission at CP2, CP3 and CP4 (stamp charging) were 146.98, 31.82, and 35.20 μg m-3, which were 13.38-, 2.90- and 3.20-fold higher, respectively, than those at CP1 (top charging, 10.98 μg m-3). Low molecular weight PAHs with 2-3 rings made up 75.3% of the total PAHs on average, and the contributions of particulate PAH to the total BaP equivalent concentrations (BaPeq) in each plant were significantly higher than the corresponding contributions to the total PAH mass concentrations. The calculated total BaPeq concentrations varied from 0.19 to 10.86 μg m-3 with an average of 3.14 μg m-3, and more efficient measures to control fugitive emission in coke plants should be employed to prevent or reduce the health risk to workers. Absorption into organic matter dominated the gas-particle partitioning for most of the PAHs including PhA, FluA, Chr, BbF, BkF and BaP, while adsorption on elemental carbon appeared to play a dominant role for AcPy, AcP and Flu.

  14. Origin of enhanced field emission characteristics postplasma treatment of multiwalled carbon nanotube array

    SciTech Connect

    Lee, Kyu; Lim, Seong Chu; Lee, Young Hee; Choi, Young Chul

    2008-08-11

    Field emission properties of chemical-vapor-deposition-grown multiwalled carbon nanotubes (MWCNTs) with plasma treatment have been investigated. Origin of the enhanced field emission current was interpreted in terms of surface morphology of MWCNTs, work function, field enhancement factor, and emission area. Contrary to the general belief, the change in the work function increased slightly with the plasma treatment time, whereas the field enhancement factor decreased. We found that the number of emittable MWCNTs played a dominant role in the current enhancement.

  15. Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 2: volatile and semivolatile particulate matter emissions.

    PubMed

    Williams, Paul I; Allan, James D; Lobo, Prem; Coe, Hugh; Christie, Simon; Wilson, Christopher; Hagen, Donald; Whitefield, Philip; Raper, David; Rye, Lucas

    2012-10-01

    The work characterizes the changes in volatile and semivolatile PM emissions from a gas turbine engine resulting from burning alternative fuels, specifically gas-to-liquid (GTL), coal-to-liquid (CTL), a blend of Jet A-1 and GTL, biodiesel, and diesel, to the standard Jet A-1. The data presented here, compares the mass spectral fingerprints of the different fuels as measured by the Aerodyne high resolution time-of-flight aerosol mass spectrometer. There were three sample points, two at the exhaust exit plane with dilution added at different locations and another probe located 10 m downstream. For emissions measured at the downstream probe when the engine was operating at high power, all fuels produced chemically similar organic PM, dominated by C(x)H(y) fragments, suggesting the presence of long chain alkanes. The second largest contribution came from C(x)H(y)O(z) fragments, possibly from carbonyls or alcohols. For the nondiesel fuels, the highest loadings of organic PM were from the downstream probe at high power. Conversely, the diesel based fuels produced more organic material at low power from one of the exit plane probes. Differences in the composition of the PM for certain fuels were observed as the engine power decreased to idle and the measurements were made closer to the exit plane. PMID:22913312

  16. Absorption of laser radiation by femtosecond laser-induced plasma of air and its emission characteristics

    NASA Astrophysics Data System (ADS)

    Ilyin, A. A.; Golik, S. S.; Shmirko, K. A.

    2015-11-01

    The energy absorbed by femtosecond laser plasma has nonlinear dependence on incident laser energy. The threshold power for plasma formation is 5.2 GW. Emission of nitrogen molecule, nitrogen molecule ion, atomic oxygen (unresolved triplet O I 777 nm) and nitrogen (triplet N I 742.4, 744.3 and 746.8 nm) lines is detected. Molecular emission consists of second positive and firs negative systems of nitrogen. Time-resolved spectroscopy of plasmas shows short molecular line emission (up to 1 ns) and long atomic line emission (up to 150 ns).

  17. N2O emission in short-cut simultaneous nitrification and denitrification process: dynamic emission characteristics and succession of ammonia-oxidizing bacteria.

    PubMed

    Yan, Yingyan; Li, Ping; Wu, Jinhua; Zhu, Nengwu; Wu, Pingxiao; Wang, Xiangde

    2014-01-01

    A sequencing batch airlift reactor was used to investigate the characteristics of nitrous oxide (N2O) emission and the succession of an ammonia-oxidizing bacteria (AOB) community. The bioreactor could successfully switch from the complete simultaneous nitrification and denitrification (SND) process to the short-cut SND process by increasing the influent pH from 7.0-7.3 to 8.0-8.3. The results obtained showed that, compared with the complete SND process, the TN removal rate and SND efficiency were improved in the short-cut SND process by approximately 13 and 11%, respectively, while the amount of N2O emission was nearly three times larger than that in the complete SND process. The N2O emission was closely associated to nitrite accumulation. Analysis of the AOB microbial community showed that nitrifier denitrification by Nitrosomonas-like AOB could be an important pathway for the enhancement of N2O emission in the short-cut SND process. PMID:24960019

  18. On-road emission characteristics of heavy-duty diesel vehicles in Shanghai

    NASA Astrophysics Data System (ADS)

    Chen, Changhong; Huang, Cheng; Jing, Qiguo; Wang, Haikun; Pan, Hansheng; Li, Li; Zhao, Jing; Dai, Yi; Huang, Haiying; Schipper, Lee; Streets, David G.

    On-road vehicle tests of nine heavy-duty diesel trucks were conducted using SEMTECH-D, an emissions measuring instrument provided by Sensors, Inc. The total length of roads for the tests was 186 km. Data were obtained for 37,255 effective driving cycles, including 17,216 on arterial roads, 15,444 on residential roads, and 4595 on highways. The impacts of speed and acceleration on fuel consumption and emissions were analyzed. Results show that trucks spend an average of 16.5% of the time in idling mode, 25.5% in acceleration mode, 27.9% in deceleration mode, and only 30.0% at cruise speed. The average emission factors of CO, total hydrocarbons (THC), and NO x for the selected vehicles are (4.96±2.90), (1.88±1.03) and (6.54±1.90) g km -1, respectively. The vehicle emission rates vary significantly with factors like speed and acceleration. The test results reflect the actual traffic situation and the current emission status of diesel trucks in Shanghai. The measurements show that low-speed conditions with frequent acceleration and deceleration, particularly in congestion conditions, are the main factors that aggravate vehicle emissions and cause high emissions of CO and THC. Alleviating congestion would significantly improve vehicle fuel economy and reduce CO and THC emissions.

  19. Spatiotemporal Characteristics, Determinants and Scenario Analysis of CO2 Emissions in China Using Provincial Panel Data

    PubMed Central

    Wang, Shaojian

    2015-01-01

    This paper empirically investigated the spatiotemporal variations, influencing factors and future emission trends of China’s CO2 emissions based on a provincial panel data set. A series of panel econometric models were used taking the period 1995–2011 into consideration. The results indicated that CO2 emissions in China increased over time, and were characterized by noticeable regional discrepancies; in addition, CO2 emissions also exhibited properties of spatial dependence and convergence. Factors such as population scale, economic level and urbanization level exerted a positive influence on CO2 emissions. Conversely, energy intensity was identified as having a negative influence on CO2 emissions. In addition, the significance of the relationship between CO2 emissions and the four variables varied across the provinces based on their scale of economic development. Scenario simulations further showed that the scenario of middle economic growth, middle population increase, low urbanization growth, and high technology improvement (here referred to as Scenario BTU), constitutes the best development model for China to realize the future sustainable development. Based on these empirical findings, we also provide a number of policy recommendations with respect to the future mitigation of CO2 emissions. PMID:26397373

  20. Experimental investigation on NOx emission characteristics of a new solid fuel made from sewage sludge mixed with coal in combustion.

    PubMed

    Zhai, Yunbo; Zhu, Lu; Chen, Hongmei; Xu, Bibo; Li, Caiting; Zeng, Guangming

    2015-02-01

    In this article, a new briquette fuel (SC), which was produced by the mixture of coal fines (25.9%), sewage sludge (60.6%), lignin (4.5%), tannic acid (4.5%) and elemental silicon (4.5%), was provided. Then, in a high temperature electric resistance tubular furnace, the total emissions of NO2 and NO, effects of combustion temperature, air flow rate and heating rate on NOx (NO, NO2) emissions of SC were studied during the combustion of SC; furthermore, effects of additives on hardness were also analysed, and the X-ray photoelectron spectroscopy was applied to investigate the reduced NOx emission mechanism. The research results showed that, compared with the characteristics of briquette fuel (SC0) produced only by the mixture of coal and sewage sludge (the ratio of coal to sewage sludge was the same as that of SC), the Meyer hardness of SC was 12.6% higher than that of SC0 and the emissions of NOx were 27.83% less than that of SC0 under the same combustion conditions. The NOx emissions of SC decreased with the adding of heating rate and increased with the rise of air flow rate. When the temperature was below 1000 °C, the emissions of NOx increased with the elevated temperature, however, further temperature extension will result in a decreasing in emissions of NOx. Furthermore, the X-ray photoelectron spectroscopy results proposed that the possible mechanism for the reduction of NOx emissions was nitrogen and silicon in SC to form the compounds of silicon and nitrogen at high temperatures. PMID:25649404

  1. Bioorthogonal Turn-On Probe Based on Aggregation-Induced Emission Characteristics for Cancer Cell Imaging and Ablation.

    PubMed

    Yuan, Youyong; Xu, Shidang; Cheng, Xiamin; Cai, Xiaolei; Liu, Bin

    2016-05-23

    Bioorthogonal turn-on probes have been widely utilized in visualizing various biological processes. Most of the currently available bioorthogonal turn-on probes are blue or green emissive fluorophores with azide or tetrazine as functional groups. Herein, we present an alternative strategy of designing bioorthogonal turn-on probes based on red-emissive fluorogens with aggregation-induced emission characteristics (AIEgens). The probe is water soluble and non-fluorescent due to the dissipation of energy through free molecular motion of the AIEgen, but the fluorescence is immediately turned on upon click reaction with azide-functionalized glycans on cancer cell surface. The fluorescence turn-on is ascribed to the restriction of molecular motion of AIEgen, which populates the radiative decay channel. Moreover, the AIEgen can generate reactive oxygen species (ROS) upon visible light (λ=400-700 nm) irradiation, demonstrating its dual role as an imaging and phototherapeutic agent. PMID:27079297

  2. [Process-based Emission Characteristics of Volatile Organic Compounds (VOCs) from Paint Industry in the Yangtze River Delta, China].

    PubMed

    Mo, Zi-wei; Niu, He; Lu, Si-hua; Shao, Min; Gou, Bin

    2015-06-01

    Understanding the volatile organic compounds (VOCs) emission characteristics from solvent usage industry is essential to reduce PM2.5 and O3 in Yangtze River Delta region. In this work, VOCs source characteristics of ship container, shipbuilding, wood, and automobile painting industry were measured using canister-GC-MS/FID analysis system. The results showed that VOCs emitted from these industrial sectors were mainly aromatics, such as toluene, xylene, and ethylbenzene, accounting for 79%-99% of total VOCs. The VOCs treatment facilities of activated carbon adsorption had little impact on changing the composition patterns of VOCs, while catalytic combustion treatments produced more alkenes. The combustion treatment of VOCs changed the maximum increment reactivity (MIR) of the VOCs emissions, and was thus very likely to change the ozone formation potentials. PMID:26387293

  3. Frequency characteristics of field electron emission from long carbon nanofilaments/nanotubes in a weak AC electric field

    NASA Astrophysics Data System (ADS)

    Izrael'yants, K. R.; Orlov, A. P.; Musatov, A. L.; Blagov, E. V.

    2016-05-01

    Frequency characteristics of field electron emission from long carbon nanofilaments/nanotubes in strong dc and weak ac electric fields have been investigated. A series of narrow peaks with a quality factor of up to 1100 has been discovered in the frequency range of hundreds of kilohertz. The analysis has shown that these peaks are probably associated with mechanical oscillations of the carbon nanofilaments/nanotubes driven by the ac electric field.

  4. Enhanced electrical properties and field emission characteristics of AZO/ZnO-nanowire core-shell structures.

    PubMed

    Huang, Jheng-Ming; Tsai, Shang-You; Ku, Ching-Shun; Lin, Chih-Ming; Chen, San-Yuan; Lee, Hsin-Yi

    2016-06-01

    The electrical properties and field-emission characteristics of ZnO nanowires (ZnO-NWs) fabricated using a vapor-liquid-solid method were systematically investigated. In particular, we explored the effects of Al-doped ZnO (AZO) films (thickness 4-100 nm) deposited on ZnO-NWs using an atomic layer deposition (ALD) method on the optoelectronic properties. The results show that the sheet resistance of net-like ZnO-NW structures can be significantly improved, specifically to become ∼1/1000 of the sheet resistance of the as-grown ZnO-NWs, attaining less than 10 Ω Sq(-1). The emission current density measured at the maximum field was roughly quadrupled relative to that of the as-grown ZnO-NWs. The data of the enhanced field-emission characteristics show that, with the ALD system, the AZO films of small resistance are readily coated on a structure with a high aspect ratio and the coating radius is controlled relative to the turn-on voltage and current density. The ultrathin AZO film from a one-monolayer coating process also significantly improved emission properties through modification of the effective work function at the AZO/ZnO-NW surface. PMID:27210896

  5. Comparison of the regulated air pollutant emission characteristics of real-world driving cycle and ECE cycle for motorcycles

    NASA Astrophysics Data System (ADS)

    Chiang, Hung-Lung; Huang, Pei-Hsiu; Lai, Yen-Ming; Lee, Ting-Yi

    2014-04-01

    Motorcycles are an important means of transportation, and their numbers have increased significantly in recent years. However, motorcycles can emit significant amounts of air pollutants; therefore, the emission characteristics and driving patterns of motorcycles are necessary baseline information for the implementation of control measures for motorcycles in urban areas. The selected motorcycles were equipped with global positioning systems (GPS) to obtain speed-time data for determination of the characteristics of real-world driving parameters, and an on-board exhaust gas analyser with data logger was employed to determine the instantaneous concentration of regulated air pollutants from motorcycle exhaust. Results indicated that the time proportions of acceleration, cruising, and deceleration are different from those of the Economic Commission for Europe (ECE) driving cycle, and the time percentages of acceleration and deceleration of the ECE cycle are much less than those in Taichung city. In general, the emission factors of the Taichung motorcycle driving cycle (TMDC) were higher HC and lower NOx emission than those of the ECE cycle. The average fuel consumption of tested motorcycles on three roads during workdays was 5% higher than that on weekends. The fuel consumption in the real-world motorcycle driving cycle was also about 7% higher than that of the ECE cycle, which again indicates that the ECE cycle is unsuitable for measuring fuel consumption in the Taichung metropolitan area. Therefore, understanding the local driving cycle is necessary for developing accurate emission data for air pollution control measures for urban areas.

  6. Fuel characteristics and emissions from biomass burning and land-use change in Nigeria.

    PubMed

    Isichei, A O; Muoghalu, J I; Akeredolu, F A; Afolabi, O A

    1995-01-01

    Nigeria is one of the 13 low-latitude countries that have significant biomass burning activities. Biomass burning occurs in moist savanna, dry forests, and forest plantations. Fires in the forest zone are associated with slash-and-burn agriculture; the areal extent of burning is estimated to be 80% of the natural savanna. In forest plantations, close to 100% of litter is burned. Current estimates of emissions from land-use change are based on a 1976 national study and extrapolations from it. The following non-carbon dioxide (CO2) trace gas emissions were calculated from savanna burning: methane (CH4), 145 gigagrams (Gg); carbon monoxide (CO), 3831 Gg; nitrous oxide (N2O), 2 Gg; and nitrogen oxides (NOx), 49 Gg. Deforestation rates in forests and woodlands are 300 × 10(3) ha (kilohectare, or kha) and 200 × kha per year, respectively. Trace gas emissions from deforestation were estimated to be 300 Gg CH4, 2.4 Gg N2O, and 24 Gg NOx. CO2 emissions from burning, decay of biomass, and long-term emissions from soil totaled 125 561 Gg. These estimates should be viewed as preliminary, because greenhouse gas emission inventories from burning, deforestation, and land-use change require two components: fuel load and emission factors. Fuel load is dependent on the areal extent of various land uses, and the biomass stocking and some of these data in Nigeria are highly uncertain. PMID:24197951

  7. Bioaerosol emission rate and plume characteristics during land application of liquid class B biosolids.

    PubMed

    Tanner, Benjamin D; Brooks, John P; Haas, Charles N; Gerba, Charles P; Pepper, Ian L

    2005-03-15

    This study investigated bioaerosol emission rates and plume characteristics of bioaerosols generated during land application of liquid Class B biosolids. In addition, it compared the rate of aerosolization of coliphages and total coliform bacteria during land application of liquid Class B biosolids to the rate of aerosolization during land application of groundwater inoculated with similar concentrations of Escherichia coli and coliphage MS2. Air samples were taken immediately downwind of a spray applicator as it applied liquid (approximately 8% solids) biosolids to farmland near Tucson, Arizona. Air samples were also collected immediately downwind of groundwater seeded with MS2 and E. coli applied to land in an identical manner. Air samples, collected with liquid impingers, were taken in horizontal and vertical alignment with respect to the passing spray applicator. Vertical and horizontal sample arrays made it possible to calculate the flux of microorganisms through a virtual plane of air samplers, located 2 m downwind of the passing spray applicator. Neither coliphages nor coliform bacteria were detected in air downwind of spray application of liquid Class B biosolids. Based on limits of detection for the methodology, the rate of aerosolization during land application of liquid biosolids was calculated to be less than 33 plaque forming units (PFU) of coliphage and 10 colony forming units (CFU) of coliform bacteria per meter traveled by the spray applicator. The rate of aerosolization during land application of seeded groundwater was found to be, on average, 2.02 x 10(3) CFU E. coli and 3.86 x 10(3) PFU MS2 aerosolized per meter traveled by the spray applicator. This is greater aerosolization than was observed during land application of biosolids. Because concentrations of coliphages and coliforms were similar in the liquid biosolids and the seeded water, itwas concluded that some property of biosolids reduces aerosolization of microorganisms relative to

  8. Methane emissions from beef and dairy cattle: quantifying the effect of physiological stage and diet characteristics.

    PubMed

    Ricci, P; Rooke, J A; Nevison, I; Waterhouse, A

    2013-11-01

    The prediction of methane outputs from ruminant livestock data at farm, national, and global scales is a vital part of greenhouse gas calculations. The objectives of this work were to quantify the effect of physiological stage (lactating or nonlactating) on predicting methane (CH4) outputs and to illustrate the potential improvement for a beef farming system of using more specific mathematical models to predict CH4 from cattle at different physiological stages and fed different diet types. A meta-analysis was performed on 211 treatment means from 38 studies where CH4, intake, animal, and feed characteristics had been recorded. Additional information such as type of enterprise, diet type, physiological stage, CH4 measurement technique, intake restriction, and CH4 reduction treatment application from these studies were used as classificatory factors. A series of equations for different physiological stages and diet types based on DMI or GE intake explained 96% of the variation in observed CH4 outputs (P<0.001). Resulting models were validated with an independent dataset of 172 treatment means from 20 studies. To illustrate the scale of improvement on predicted CH4 outputs from the current whole-farm prediction approach (Intergovernmental Panel on Climate Change [IPCC]), equations developed in the present study (NewEqs) were compared with the IPCC equation {CH4 (g/d)=[(GEI×Ym)×1,000]/55.65}, in which GEI is GE intake and Ym is the CH4 emission factor, in calculating CH4 outputs from 4 diverse beef systems. Observed BW and BW change data from cows with calves at side grazing either hill or lowland grassland, cows and overwintering calves and finishing steers fed contrasting diets were used to predict energy requirements, intake, and CH4 outputs. Compared with using this IPCC equation, NewEqs predicted up to 26% lower CH4 on average from individual lactating grazing cows. At the herd level, differences between equation estimates from 10 to 17% were observed in total

  9. Sources and characteristics of acoustic emissions from mechanically stressed geologic granular media — A review

    NASA Astrophysics Data System (ADS)

    Michlmayr, Gernot; Cohen, Denis; Or, Dani

    2012-05-01

    The formation of cracks and emergence of shearing planes and other modes of rapid macroscopic failure in geologic granular media involve numerous grain scale mechanical interactions often generating high frequency (kHz) elastic waves, referred to as acoustic emissions (AE). These acoustic signals have been used primarily for monitoring and characterizing fatigue and progressive failure in engineered systems, with only a few applications concerning geologic granular media reported in the literature. Similar to the monitoring of seismic events preceding an earthquake, AE may offer a means for non-invasive, in-situ, assessment of mechanical precursors associated with imminent landslides or other types of rapid mass movements (debris flows, rock falls, snow avalanches, glacier stick-slip events). Despite diverse applications and potential usefulness, a systematic description of the AE method and its relevance to mechanical processes in Earth sciences is lacking. This review is aimed at providing a sound foundation for linking observed AE with various micro-mechanical failure events in geologic granular materials, not only for monitoring of triggering events preceding mass mobilization, but also as a non-invasive tool in its own right for probing the rich spectrum of mechanical processes at scales ranging from a single grain to a hillslope. We review first studies reporting use of AE for monitoring of failure in various geologic materials, and describe AE generating source mechanisms in mechanically stressed geologic media (e.g., frictional sliding, micro-crackling, particle collisions, rupture of water bridges, etc.) including AE statistical features, such as frequency content and occurrence probabilities. We summarize available AE sensors and measurement principles. The high sampling rates of advanced AE systems enable detection of numerous discrete failure events within a volume and thus provide access to statistical descriptions of progressive collapse of systems

  10. Emissions characteristics of cooling towers using reclaimed wastewater in california. Final report, July 1979-July 1981

    SciTech Connect

    Rogozen, M.B.; Phillips, A.R.; Guttman, M.A.; Shokes, R.F.; Fargo, L.

    1981-08-11

    Present and planned use of reclaimed municipal wastewater, industrial process water, and geothermal condensate as makeup to cooling towers have raised questions about the potential for atmospheric emissions of pathogenic microorganisms, organic compounds, heavy metals, and other wastewater constituents. In this study, the makeup and circulating water of six towers were sampled and analyzed for indicator bacteria and virus, volatile and nonvolatile organic compounds, metals, and other components of potential concern. Further water sampling and exhaust air emissions tests were then conducted on four of the towers; for the microbiological emissions tests, a special isokinetic sampling device was developed and employed.

  11. Emission characteristics of a premix combustor fueled with a simulated partial-oxidation product gas

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1979-01-01

    A two-stage gas turbine combustor concept employing a very fuel-rich partial oxidation stage is being explored for broadening the combustion margin between ultralow emissions and the lean stability limit. Combustion and emission results are presented for a series of experiments where a simulated partial oxidation product gas was used in a premix combustor operated with inlet air state conditions typical of cruise power for high-performance aviation engines (12 atm and 850 F). Ultralow NOx, CO, and HC emissions and an extended lean burning limit were achieved simultaneously.

  12. Near-infrared fluorescence amplified organic nanoparticles with aggregation-induced emission characteristics for in vivo imaging

    NASA Astrophysics Data System (ADS)

    Geng, Junlong; Zhu, Zhenshu; Qin, Wei; Ma, Lin; Hu, Yong; Gurzadyan, Gagik G.; Tang, Ben Zhong; Liu, Bin

    2013-12-01

    Near-infrared (NIR) fluorescence signals are highly desirable to achieve high resolution in biological imaging. To obtain NIR emission with high brightness, fluorescent nanoparticles (NPs) are synthesized by co-encapsulation of 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl)phenylamino)phenyl)fumaronitrile (TPETPAFN), a luminogen with aggregation-induced emission (AIE) characteristics, and a NIR fluorogen of silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (NIR775) using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] as the encapsulation matrix. The good spectral overlap between the emission of TPETPAFN and the absorption of NIR775 leads to efficient energy transfer, resulting in a 47-fold enhancement of the NIR775 emission intensity upon excitation of TPETPAFN at 510 nm as compared to that upon direct excitation of NIR775 at 760 nm. The obtained fluorescent NPs show sharp NIR emission with a band width of 20 nm, a large Stokes shift of 275 nm, good photostability and low cytotoxicity. In vivo imaging study reveals that the synthesized NPs are able to provide high fluorescence contrast in live animals. The Förster resonance energy transfer strategy overcomes the intrinsic limitation of broad emission spectra for AIE NPs, which opens new opportunities to synthesize organic NPs with high brightness and narrow emission for potential applications in multiplex sensing and imaging.Near-infrared (NIR) fluorescence signals are highly desirable to achieve high resolution in biological imaging. To obtain NIR emission with high brightness, fluorescent nanoparticles (NPs) are synthesized by co-encapsulation of 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl)phenylamino)phenyl)fumaronitrile (TPETPAFN), a luminogen with aggregation-induced emission (AIE) characteristics, and a NIR fluorogen of silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (NIR775) using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000

  13. Investigation of mid-infrared emission characteristics and energy transfer dynamics in Er3+ doped oxyfluoride tellurite glass

    PubMed Central

    Chen, Fangze; Wei, Tao; Jing, Xufeng; Tian, Ying; Zhang, Junjie; Xu, Shiqing

    2015-01-01

    Er3+ doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Ωt (t = 2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s−1), emission cross section σem (10.18 × 10−21 cm2) and σem × Δλeff (945.32 × 10−28 cm3), corresponding to the 2.7 μm emission of Er3+: 4I11/2→ 4I13/2 transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er3+ concentration. The calculation results show that with the increment of Er3+ concentration, the energy transfer up-conversion rate of 4I13/2 state increases while the rate of 4I11/2 state reduces, resulting in the change of 2.7 μm emission. PMID:26032900

  14. Influence of ethanol-gasoline blended fuel on emission characteristics from a four-stroke motorcycle engine.

    PubMed

    Jia, Li-Wei; Shen, Mei-Qing; Wang, Jun; Lin, Man-Qun

    2005-08-31

    Emission characteristics from a four-stroke motorcycle engine using 10% (v/v) ethanol-gasoline blended fuel (E10) were investigated at different driving modes on the chassis dynamometers. The results indicate that CO and HC emissions in the engine exhaust are lower with the operation of E10 as compared to the use of unleaded gasoline, whereas the effect of ethanol on NO(X) emission is not significant. Furthermore, species of both unburned hydrocarbons and their ramifications were analyzed by the combination of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization detection (GC/FID). This analysis shows that aromatic compounds (benzene, toluene, xylene isomers (o-xylene, m-xylene and p-xylene), ethyltoluene isomers (o-ethyltoluene, m-ethyltoluene and p-ethyltoluene) and trimethylbenzene isomers (1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene)) and fatty group ones (ethylene, methane, acetaldehyde, ethanol, butene, pentane and hexane) are major compounds in motorcycle engine exhaust. It is found that the E10-fueled motorcycle engine produces more ethylene, acetaldehyde and ethanol emissions than unleaded gasoline engine does. The no significant reduction of aromatics is observed in the case of ethanol-gasoline blended fuel. The ethanol-gasoline blended fuel can somewhat improve emissions of the rest species. PMID:15923082

  15. Aerosol emissions by tropical forest and savanna biomass burning: Characteristic trace elements and fluxes

    SciTech Connect

    Echalar, F.; Gaudichet, A.; Cachier, H.

    1995-11-15

    This report characterizes and compares trace element emissions from fires of three different types of savannas and from the southwestern amazonian rain forest. This study tries to verify a fingerprint that may characterize savanna fires or tropical biomass burning.

  16. Seasonal CH4 and N2O emissions and plant growth characteristics of several cultivars in direct seeded rice systems

    NASA Astrophysics Data System (ADS)

    Simmonds, M.; Anders, M. M.; Adviento-Borbe, M. A.; Van Kessel, C.; McClung, A.; Linquist, B.

    2014-12-01

    Understanding cultivar effects on field greenhouse gas (GHG) emissions in rice (Oryza sativa L.) systems is needed to improve the accuracy of predictive models used for estimating GHG emissions, and to determine to what extent choice of cultivar may have on GHG mitigation. We compared CH4 and N2O emissions, global warming potential (GWP = N2O + CH4), yield-scaled GWP (GWPY = GWP Mg-1 grain), and plant growth characteristics of 8 cultivars within 4 study sites in California and Arkansas. Seasonal CH4 emissions differed between cultivars by a factor of 2.1 and 1.3 at one California and one Arkansas site, respectively. Nitrous oxide emissions were negligible, comprised <10% of GWP, and were not different among cultivars. When sites and cultivars were pooled, and data were normalized to site averages, there was a positive correlation (r = 0.33) between root biomass at heading and seasonal CH4 emissions, but no correlation with shoot biomass at heading, or grain or straw biomass at maturity. Although differences in GWP and GWPY were observed, the consistency of some of the trends was variable across sites, indicating the importance of the genotype x environment interaction. While no high-yielding and low CH4-emitting cultivars were identified at the California sites, among the Southern varieties tested at the Arkansas site, the lowest emitting cultivar had the highest yield. This highlights the potential for breeding high-yielding varieties with low GWP, the ideal scenario to achieve low GWPY due to simultaneously mitigating GHG emissions and improving global food security.

  17. Emission characteristics of co-combustion of sewage sludge with olive cake and lignite coal in a circulating fluidized bed.

    PubMed

    Toraman, Oner Yusuf; Topal, Hüseyin; Bayat, Oktay; Atimtay, Aysel T

    2004-01-01

    In this study, a circulating fluidized bed (CFB) of 125 mm diameter and 1800mm height was used to find the combustion characteristics of sewage sludge (SS) produced in Turkey. Sludge + olive cake, and sludge + lignite coal mixtures were burned separately. Various sludge-to-lignite coal and sludge-to-olive cake ratios (5/95, 10/90, 15/85, 20/80) were tried. On-line concentrations of major components (O2, SO2, CO2, CO, NOx, CmHn) were measured in the flue gas, as well as temperature and pressure distributions along the bed. Combustion efficiencies of sludge + olive cake and sludge + lignite coal mixtures were calculated, and the optimum conditions for operating parameters were discussed. The results have shown that the combustion mainly takes place in the upper regions of the main column where the temperature reaches 900 degrees C. SS + Coal burn in the CFB with an efficiency of 95.14% to 96.18%, which is considered to be quite good. When burning sludge mixed with olive cake, appreciable amounts of CO and unburned hydrocarbons are formed and the combustion efficiency drops to 92.93%. CO and CmHn emissions are lower when lignite coal is mixed with various amounts of SS than the emissions when the coal is burned alone. As the %SS is increased in the fuel mixture, the SO2 emission decreases. NOx emissions are slightly higher. When burning sludge mixed with olive cake, SO2 and NOx emissions are slightly higher. CO and CmHn emissions decrease sharply when SS is mixed with 5%wt. olive cake. With increasing sludge ratio these emissions increase due to the unburned hydrocarbons. As a result of this study, it is believed that SS can be burned effectively in a CFBC together with other fuels, especially with olive cake (OC). OC will be a good additive fuel for the combustion of lower quality fuels. PMID:15137713

  18. Greenhouse gas emissions from MSW incineration in China: impacts of waste characteristics and energy recovery.

    PubMed

    Yang, Na; Zhang, Hua; Chen, Miao; Shao, Li-Ming; He, Pin-Jing

    2012-12-01

    Determination of the amount of greenhouse gas (GHG) emitted during municipal solid waste incineration (MSWI) is complex because both contributions and savings of GHGs exist in the process. To identify the critical factors influencing GHG emissions from MSWI in China, a GHG accounting model was established and applied to six Chinese cities located in different regions. The results showed that MSWI in most of the cities was the source of GHGs, with emissions of 25-207 kg CO(2)-eq t(-1) rw. Within all process stages, the emission of fossil CO(2) from the combustion of MSW was the main contributor (111-254 kg CO(2)-eq t(-1) rw), while the substitution of electricity reduced the GHG emissions by 150-247 kg CO(2)-eq t(-1) rw. By affecting the fossil carbon content and the lower heating value of the waste, the contents of plastic and food waste in the MSW were the critical factors influencing GHG emissions of MSWI. Decreasing food waste content in MSW by half will significantly reduce the GHG emissions from MSWI, and such a reduction will convert MSWI in Urumqi and Tianjin from GHG sources to GHG sinks. Comparison of the GHG emissions in the six Chinese cities with those in European countries revealed that higher energy recovery efficiency in Europe induced much greater reductions in GHG emissions. Recovering the excess heat after generation of electricity would be a good measure to convert MSWI in all the six cities evaluated herein into sinks of GHGs. PMID:22796016

  19. Greenhouse gas emissions from MSW incineration in China: Impacts of waste characteristics and energy recovery

    SciTech Connect

    Yang Na; Zhang Hua; Chen Miao; Shao Liming; He Pinjing

    2012-12-15

    Determination of the amount of greenhouse gas (GHG) emitted during municipal solid waste incineration (MSWI) is complex because both contributions and savings of GHGs exist in the process. To identify the critical factors influencing GHG emissions from MSWI in China, a GHG accounting model was established and applied to six Chinese cities located in different regions. The results showed that MSWI in most of the cities was the source of GHGs, with emissions of 25-207 kg CO{sub 2}-eq t{sup -1} rw. Within all process stages, the emission of fossil CO{sub 2} from the combustion of MSW was the main contributor (111-254 kg CO{sub 2}-eq t{sup -1} rw), while the substitution of electricity reduced the GHG emissions by 150-247 kg CO{sub 2}-eq t{sup -1} rw. By affecting the fossil carbon content and the lower heating value of the waste, the contents of plastic and food waste in the MSW were the critical factors influencing GHG emissions of MSWI. Decreasing food waste content in MSW by half will significantly reduce the GHG emissions from MSWI, and such a reduction will convert MSWI in Urumqi and Tianjin from GHG sources to GHG sinks. Comparison of the GHG emissions in the six Chinese cities with those in European countries revealed that higher energy recovery efficiency in Europe induced much greater reductions in GHG emissions. Recovering the excess heat after generation of electricity would be a good measure to convert MSWI in all the six cities evaluated herein into sinks of GHGs.

  20. Positron emission tomography displacement sensitivity: predicting binding potential change for positron emission tomography tracers based on their kinetic characteristics.

    PubMed

    Morris, Evan D; Yoder, Karmen K

    2007-03-01

    There is great interest in positron emission tomography (PET) as a noninvasive assay of fluctuations in synaptic neurotransmitter levels, but questions remain regarding the optimal choice of tracer for such a task. A mathematical method is proposed for predicting the utility of any PET tracer as a detector of changes in the concentration of an endogenous competitor via displacement of the tracer (a.k.a., its 'vulnerability' to competition). The method is based on earlier theoretical work by Endres and Carson and by the authors. A tracer-specific predictor, the PET Displacement Sensitivity (PDS), is calculated from compartmental model simulations of the uptake and retention of dopaminergic radiotracers in the presence of transient elevations of dopamine (DA). The PDS predicts the change in binding potential (DeltaBP) for a given change in receptor occupancy because of binding by the endogenous competitor. Simulations were performed using estimates of tracer kinetic parameters derived from the literature. For D(2)/D(3) tracers, the calculated PDS indices suggest a rank order for sensitivity to displacement by DA as follows: raclopride (highest sensitivity), followed by fallypride, FESP, FLB, NMSP, and epidepride (lowest). Although the PDS takes into account the affinity constant for the tracer at the binding site, its predictive value cannot be matched by either a single equilibrium constant, or by any one rate constant of the model. Values for DeltaBP have been derived from published studies that employed comparable displacement paradigms with amphetamine and a D(2)/D(3) tracer. The values are in good agreement with the PDS-predicted rank order of sensitivity to displacement. PMID:16788713

  1. Emission characteristics for polycyclic aromatic hydrocarbons from solid fuels burned in domestic stoves in rural China

    PubMed Central

    SHEN, Guofeng; TAO, Shu; Chen, Yuanchen; Zhang, Yanyan; Wei, Siye; Xue, Miao; Wang, Bin; WANG, Rong; LV, Yan; LI, Wei; SHEN, Huizhong; HUANG, Ye; CHEN, Han

    2014-01-01

    Emission characterization of polycyclic aromatic hydrocarbons (PAHs) from residential combustion of crop residues, woody material, coal, and biomass pellets in domestic stoves in rural China are compared in term of emission factors (EFs), influencing factors, composition profiles, isomer ratios and phase distributions. The EFs of PAHs vary by two orders of magnitude among fuel types suggesting that a detailed fuel categorization is useful in the development of an emission inventory and potential in emission abatement of PAHs by replacing dirty fuels with relatively cleaner ones. The influence of fuel moisture in biomass burning is non-linear. Biofuels with very low moisture display relatively high emissions as do fuels with very high moisture. Bituminous coals and brushwood yield relatively large fractions of high molecular PAHs. The emission factor of Benzo(a)pyrene equivalent quantity for raw bituminous coal is as high as 52 mg/kg, which is 1–2 orders of magnitude higher than the other fuels. For source diagnosis, high molecular weight isomers are more informative than low molecular weight ones and multiple ratios could be used together whenever possible. PMID:24245776

  2. Stabilizing a gaseous optical laser

    NASA Technical Reports Server (NTRS)

    Jauan, A.; Shimoda, K.

    1974-01-01

    Frequency of gaseous optical laser can be stabilized by sinusoidally modulating the geometry of the cavity. Fabry-Perot dielectric mirrors are mounted in two Invar blocks that are connected by four magnetorestrictive bars. Each bar has three coils to sinusoidally modulate system. Ac establishes frequency, and dc the average value; both are supplied to coil from control system.

  3. Infrared radiative energy transfer in gaseous systems

    NASA Technical Reports Server (NTRS)

    Tiwari, Surendra N.

    1991-01-01

    Analyses and numerical procedures are presented to investigate the radiative interactions in various energy transfer processes in gaseous systems. Both gray and non-gray radiative formulations for absorption and emission by molecular gases are presented. The gray gas formulations are based on the Planck mean absorption coefficient and the non-gray formulations are based on the wide band model correlations for molecular absorption. Various relations for the radiative flux and divergence of radiative flux are developed. These are useful for different flow conditions and physical problems. Specific plans for obtaining extensive results for different cases are presented. The procedure developed was applied to several realistic problems. Results of selected studies are presented.

  4. On-road emission characteristics of VOCs from light-duty gasoline vehicles in Beijing, China

    NASA Astrophysics Data System (ADS)

    Cao, Xinyue; Yao, Zhiliang; Shen, Xianbao; Ye, Yu; Jiang, Xi

    2016-01-01

    This study is the third in a series of three papers aimed at characterizing the VOC emissions of vehicles in Beijing. In this study, 30 light-duty vehicles fueled with gasoline were evaluated using a portable emission measurement system (PEMS) as they were driven on a predesigned, fixed test route. All of the tested vehicles were rented from private vehicle owners and spanned regulatory compliance guidelines ranging from Pre-China I to China IV. Alkanes, alkenes, aromatics and some additional species in the exhaust were collected in Tedlar bags and analyzed using gas chromatography/mass spectrometry (GC-MS). Carbonyls were collected on 2,4-dinitrophenyhydrazine (DNPH) cartridges and analyzed using high-performance liquid chromatography (HPLC). Overall, 74 VOC species were detected from the tested vehicles, including 22 alkanes, 6 alkenes, 1 alkyne, 16 aromatics, 3 cyclanes, 10 halohydrocarbons, 12 carbonyls and 4 other compounds. Alkanes, aromatics and carbonyls were the dominant VOCs with weight percentages of approximately 36.4%, 33.1% and 17.4%, respectively. The average VOC emission factors and standard deviations of the Pre-China I, China I, China II, China III and China IV vehicles were 469.3 ± 200.1, 80.7 ± 46.1, 56.8 ± 37.4, 25.6 ± 11.7 and 14.9 ± 8.2 mg/km, respectively, which indicated that the VOC emissions significantly decreased under stricter vehicular emission standards. Driving cycles also influenced the VOC emissions from the tested vehicles. The average VOC emission factors based on the travel distances of the tested vehicles under urban driving cycles were greater than those under highway driving cycles. In addition, we calculated the ozone formation potential (OFP) using the maximum incremental reactivity (MIR) method. The results of this study will be helpful for understanding the true emission levels of light-duty gasoline vehicles and will provide information for controlling VOC emissions from vehicles in Beijing, China.

  5. Radiation characteristics of a high-emissivity cylindrical-spherical cavity with obscuration.

    PubMed

    Meier, Steven R; Joseph, Richard I; Antiochos, Spiro K

    2004-01-01

    We have calculated, to first order, the apparent emissivity of the bounding diffuse surfaces of a high-emissivity cylindrical-spherical cavity enclosure. Our calculations indicate that to achieve emissivities close to a perfectly absorbing blackbody cavity along the bounding surfaces of the spherical enclosure, the radius of the sphere must be equal to or greater than a factor of 4 times the cylinder radius R(S) > or = 4R(C). Furthermore, to achieve emissivities approaching a blackbody cavity along the lower bounding surfaces of the cylindrical enclosure, the length of the cylinder must be a factor of 4 times greater than the radius of the cylinder L > or = 4R(C). In addition, we present the mathematical framework necessary to calculate radiant transfer within a cavity enclosure that contains obscuration. These results can be applied to the design of high-emissivity blackbody calibration cavities and to the reduction of stray light in terrestrial and spaceborne optical systems. PMID:14725402

  6. [Vertical distribution characteristics of N2O emission in tea garden and its adjacent woodland].

    PubMed

    Fan, Li-chao; Han, Wen-yan; Li, Xin; Li, Zhi-xin

    2015-09-01

    In this study, we determined the vertical distribution of N2O emission rates in tea soils and its adjacent woodland soils. The results showed that total nitrogen contents, N2O fluxes and cumulative emissions in the tea garden and woodland decreased with the increasing depth of the soil layer, and their average values were greater in tea garden than in woodland. Generally, pH, soil water soluble organic nitrogen (WSON), soil microbial biomass nitrogen (MBN), NO(3-)-N and NH(4+)-N contents had a downward trend with the increasing depth of soil layer. The WSON, MBN, NO(3-)-N and NH(4+)-N contents from each soil layer were greater in tea garden than in woodland, but the pH value in tea garden was lower than that in woodland. The N2O emission rate was significantly positively related with TN, MBN and NH(4+)-N contents, but not with pH value. The N2O emission rate was significantly correlated with WSON content in woodland, but not in tea garden. The N20 emission rate was significantly correlated with NO(3-)-N concentration in tea garden, but not in woodland. WSON/TN and N2O-N/SMBN were averagely greater than in tea garden in woodland, and SMBN/TN was opposite. These results indicated that tea soil was not conducive to accumulate nitrogen pool, maintain soil quality and its sustainable use compared to woodland. PMID:26785543

  7. Methane and nitrous oxide (N{sub 2}O) emission characteristics from automobiles

    SciTech Connect

    Koike, Noriyuki; Odaka, Matsuo

    1996-09-01

    Exhaust gases discharged from automobiles are noticed as one of the reasons for recent increase in atmospheric methane and nitrous oxide concentration, which have been considered as greenhouse gases. In order to make an accurate estimation of methane and nitrous oxide discharged from automobiles, measurement methods were experimentally developed and emissions were measured for different kinds of automobiles under various driving conditions. Then, the authors have tried to estimate the annual global emissions from automobiles using these measurement results and statistical data such as the number of automobiles, the total annual mileage, and the total annual fuel consumption, etc. The emissions from passenger vehicles which have been estimated from the global number of automobiles were 477.263 t/year for methane and 313.472 t/year for nitrous oxide. These numbers are higher than what had been estimated.

  8. The Characteristics of Dielectric Barrier Discharge and its Influence on the Excimer XeCl* Emission

    NASA Astrophysics Data System (ADS)

    Xu, Jing-zhou; Liu, Wei; Liang, Rong-qing; Ren, Zhao-xing

    2001-12-01

    In this work, the influence of discharge modes on the excimer XeCl* emission (308 nm) has been studied by adding helium gas into the xenon and chlorine mixture. It is found that the transition from filament discharge to glow/filament-combined discharge leads to the decrease in excimer emission. We are the first one to use a flowing water film as an outer transparent electrode, and achieve a higher UV intensity, compared with the case by using a metal mesh as the outer electrode. The influence of the gas temperature both in the reactor Tg and in a discharge channel Tc on the excimer emission has been analyzed preliminarily. Finally, it has been expected that the replacement of chlorine gas Cl2 by another chlorine gas may reduce the heat generated in the discharge processes and give rise to the excimer XeCl* radiation.

  9. Characteristics of wall sheath and secondary electron emission under different electron temperatures in a Hall thruster

    NASA Astrophysics Data System (ADS)

    Duan, Ping; Qin, Hai-Juan; Zhou, Xin-Wei; Cao, An-Ning; Chen, Long; Gao, Hong

    2014-07-01

    In this paper, a two-dimensional physical model is established in a Hall thruster sheath region to investigate the influences of the electron temperature and the propellant on the sheath potential drop and the secondary electron emission in the Hall thruster, by the particle-in-cell (PIC) method. The numerical results show that when the electron temperature is relatively low, the change of sheath potential drop is relatively large, the surface potential maintains a stable value and the stability of the sheath is good. When the electron temperature is relatively high, the surface potential maintains a persistent oscillation, and the stability of the sheath reduces. As the electron temperature increases, the secondary electron emission coefficient on the wall increases. For three kinds of propellants (Ar, Kr, and Xe), as the ion mass increases the sheath potentials and the secondary electron emission coefficients reduce in sequence.

  10. Coherent detection of metal-metal terahertz quantum cascade lasers with improved emission characteristics

    SciTech Connect

    Brewer, Anthony; Beere, Harvey E.; Ritchie, David A.; Freeman, Joshua R. Cavalié, Pierrick; Maysonnave, Jean; Tignon, Jérôme; Dhillon, Sukhdeep S.

    2014-02-24

    Coherent detection of emission from quantum cascade lasers with metal-metal waveguides is demonstrated through free-space coupling of a THz pulse to the sub-wavelength waveguide. We implement a simple, monolithic planar horn antenna design on the metal-metal waveguide that reduces the impedance mis-match to the waveguide. The resulting devices show up to 10 times more directed output power than conventional metal-metal waveguides. This enhanced coupling to free-space allows a more efficient injection of broad-band THz pulses into the waveguide. Through this, we are able to seed the laser emission and coherently detect the laser emission by electro-optic sampling.

  11. On-road emission characteristics of VOCs from diesel trucks in Beijing, China

    NASA Astrophysics Data System (ADS)

    Yao, Zhiliang; Shen, Xianbao; Ye, Yu; Cao, Xinyue; Jiang, Xi; Zhang, Yingzhi; He, Kebin

    2015-02-01

    This paper is the first in our series of papers aimed at understanding the volatile organic compound (VOC) emissions of vehicles in Beijing by conducting on-board emission measurements. This paper focuses on diesel vehicles. In this work, 18 China III diesel vehicles, including seven light-duty diesel trucks (LDDTs), four medium-duty diesel trucks (MDDTs) and seven heavy-duty diesel trucks (HDDTs), were examined when the vehicles were driven on predesigned fixed test routes in Beijing in China using a portable emissions measurement system (PEMS). Tedlar bag sampling and 2,4-dinitrophenyhydrazine (DNPH) cartridge sampling were used to collect VOC species, and gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) were used to analyze these samples. We obtained the VOC emission factors and relative compositions for diesel trucks of different sizes under different driving patterns. In total, 64 VOC species were quantified in this study, including 25 alkanes, four alkenes, 13 aromatics, 13 carbonyls and nine other compounds. The emission factors of the total VOCs based on mileage traveled for HDDTs were higher than those of LDDTs and MDDTs. Carbonyls, aromatics and alkanes were the dominant VOC species. Carbonyls accounted for 42.7%-69.2% of the total VOCs in the three types of tested diesel trucks. The total VOC emission factors of the tested vehicles that were driven on non-highway routes were 1.5-2.0 times higher than those of the vehicles driven on the highway. As for the OFP calculation results, with increased vehicle size, the ozone formation potential presented an increasing trend. Among the VOC components, carbonyls were the primary contributor to OFP. In addition, the OFPs under non-highway driving cycles were 1.3-1.7 times those under highway driving cycles. The results of this study will be helpful in improving our understanding of VOCs emitted from on-road diesel trucks in China.

  12. Characteristics of the soft X-ray emission from laser-produced highly charged platinum plasmas

    NASA Astrophysics Data System (ADS)

    Hara, Hiroyuki; Arai, Goki; Kondo, Yoshiki; Dinh, Thanh-Hung; Dunne, Padraig; O’Sullivan, Gerry; Ejima, Takeo; Hatano, Tadashi; Jiang, Weihua; Nishikino, Masaharu; Sasaki, Akira; Sunahara, Atsushi; Higashiguchi, Takeshi

    2016-06-01

    We characterized the spectral structure of the soft X-ray emission and determined the plasma parameters in laser-produced highly charged platinum plasmas. The spectral structure observed originated from Pt21+ to Pt34+ ions, emissions from which overlapped to produce a high output flux in the carbon-window soft X-ray spectral region. Using dual laser pulse irradiation, we observed the maximum output flux, which was 20% larger than that obtained under single-laser irradiation, and the evolution of a strongly absorbed spectral structure, which was attributed to the effects of both opacity and long-scale length of the expanding pre-plasma.

  13. Field emission characteristics of a graphite nanoneedle cathode and its application to scanning electron microscopy

    SciTech Connect

    Neo, Yoichiro; Mimura, Hidenori; Matsumoto, Takahiro

    2006-02-13

    A high-brightness electron beam of more than 10{sup 11} A sr{sup -1} m{sup -2} was achieved from a graphite nanoneedle cathode, which was fabricated by simple hydrogen plasma etching of a graphite rod. A field emission was obtained at a high residual pressure of 10{sup -6} Torr. The performance of this cold cathode was demonstrated by the fabrication of a scanning electron microscope, which was operated at a high residual pressure of 10{sup -5}-10{sup -6} Torr. The brightness of this cathode offers a convenient field electron emission source that does not require a massive ultrahigh vacuum system.

  14. Military Aircraft Emissions Research - Case of Hercules Cargo Plane (C-130H) Emissions

    SciTech Connect

    Cheng, Mengdawn; Corporan, E.; DeWitt, M.; Harris, B.; Hashmonay, R.; Holdren, M.; Kaganan, R.; Spicer, C.

    2007-01-01

    Tactical airlifter like C-130H has been in use for more than 50 years, and is expected to serve for many years to come. However, the emission characteristics data of the aircraft are scarce. To increase our understanding of turboprop engine emissions, emissions from a military C-130H cargo aircraft were characterized in field conditions in the fall of 2005. Particulate and gaseous pollutants were measured by conventional and advanced instrumentation platforms that were built with in-situ extractive or remote optical sensing technologies. The measurements performed at the C-130H engine exhaust exit showed increased levels of emissions as the engine power setting increased. In contrast, there was no such a relationship found for the C-130H emitted particulate matter (as a function of engine power setting) measured at about 15-m downstream of the engine exhaust plane. The emitted gaseous species measured at both locations were, however, proportional to the engine power setting and comparable (at both locations) when corrected for ambient dilution indicating the lack of particulate emission-power setting relationship at the far field is unique. The result clearly indicates that the aircraft emission factor or index for particulate matter cannot be experimentally determined at a downstream location away from the exhaust exit and has to be determined right at the engine exhaust plane. Emission indices that are needed for air quality modeling will be presented.

  15. Enhanced field emission characteristics of boron doped diamond films grown by microwave plasma assisted chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Koinkar, Pankaj M.; Patil, Sandip S.; Kim, Tae-Gyu; Yonekura, Daisuke; More, Mahendra A.; Joag, Dilip S.; Murakami, Ri-ichi

    2011-01-01

    Boron doped diamond films were synthesized on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) technique. The effect of B 2O 3 concentration varied from 1000 to 5000 ppm on the field emission characteristics was examined. The surface morphology and quality of films were characterized by scanning electron microscope (SEM) and Raman spectroscopy. The surface morphology obtained by SEM showed variation from facetted microcrystal covered with nanometric grains to cauliflower of nanocrystalline diamond (NCD) particles with increasing B 2O 3 concentration. The Raman spectra confirm the formation of NCD films. The field emission properties of NCD films were observed to improve upon increasing boron concentration. The values of the onset field and threshold field are observed to be as low as 0.36 and 0.08 V/μm, respectively. The field emission current stability investigated at the preset value of ˜1 μA is observed to be good, in each case. The enhanced field emission properties are attributed to the better electrical conductivity coupled with the nanometric features of the diamond films.

  16. Mid-infrared emission characteristic and energy transfer of Ho3+-doped tellurite glass sensitized by Tm 3+.

    PubMed

    Chen, G X; Zhang, Q Y; Yang, G F; Jiang, Z H

    2007-05-01

    We report on 2.0-microm emission characteristic and energy transfer of Ho3+-doped tellurite glass sensitized by Tm3+ upon excitation of a conventional 808 nm laser diode. The Judd-Ofelt strength parameters, spontaneous radiative transition probabilities and radiative lifetime of Ho3+ have been calculated from the absorption spectra by using the Judd-Ofelt theory. Significant enhancement of 2.0-microm emission of Ho3+ has been observed with increasing Tm3+ doping up to 0.7 mol%. The energy transfer coefficient of the forward Tm3+-->Ho3+ is approximately 17 times larger than that of the backward Tm3+<--Ho3+ energy transfer. Our result indicates that the maximum gain of 2.0-microm emission, assigned to the transition of (5)I7-->(5)I8 of Ho3+, might be achieved from the tellurite glass at the concentration of 0.5 mol% of Tm2O3 and 0.15 mol% of Ho2O3. The high gain coefficient and quantum efficiency (1.16) along with the large value of the product of the stimulated emission cross-section and the measured radiative lifetime (4.12 x 10(-27) m(2)s) of the Ho3+/Tm3+-codoped tellurite glasses might find potential applications in efficient 2.0-microm laser. PMID:17393285

  17. A study on characteristics of Methane emission from a periodically irrigated paddy field in Japan

    NASA Astrophysics Data System (ADS)

    Wakikuromaru, N.; Iwata, T.; Yagi, K.

    2014-12-01

    Methane (CH4) is generated by organic matter decomposition in the anaerobic soil. Paddy field is one of the most important eco-system in monsoon Asia. It is said that about 10% of CH4sources is paddy fields (IPCC AR4, 2007). In this study, methane emission from a single-rice crop field was estimated by long-term micrometeorological measurements. Methane emission was calculated by the aerodynamic gradient technique from January 2011 to August 2014. Intermittent water management was carried out during cultivation period at the observational site, HCH, located in Okayama, Japan. 3-days flood and 4-days drained condition were regularly repeated from late-June to early October. Seasonal variations of CH4flux for irrigation term from 2011 to 2013 were shown in Fig.1. Remarkably large fluxes were shown at early stage of irrigation term in 2011.It seemed to be caused by the relatively longer flooded condition that the first flooded period was 20 days. Flux in 2012 was smaller than in other year through the entire irrigation period. Rapid rise in flux for early August and gradual decrease between late August and September were shown in 2013. Fluxes under drained condition showed larger emission than under flooded condition. Cumulative CH4 emissions during cultivated period from 2011 to 2013 were estimated 15.7, 8.6, and 12.9 gC/m2, respectively.

  18. The global characteristics of atmospheric emissions in the lower thermosphere and their aeronomic implications

    NASA Technical Reports Server (NTRS)

    Reed, E. I.; Chandra, S.

    1975-01-01

    The green line (555.7 nm) of atomic oxygen and the Herzberg bands of molecular oxygen (measured between 250 and 280 nm) as observed from the Ogo 4 airglow photometer from August 1967 through January 1968 are discussed in terms of their spatial and temporal distributions and their relation to the atomic oxygen content in the lower thermosphere. Daily maps of the distribution of emissions show considerable structure (cells, patches, and bands) with appreciable changes from day to day. When data are averaged over periods of several days in length, the resulting patterns have only occasional tendencies to follow geomagnetic parallels. The seasonal variation is characterized by maxima in both the Northern and Southern Hemispheres in October, the Northern Hemisphere having substantially higher emission rates. These maxima tend to move toward the poles, leaving very low values of emission at low latitudes in December and January. Noting the similarity of the atomic oxygen profiles in the lower thermosphere to the profile of a Chapman distribution, formulae are derived relating the vertical column emission rates of the green line and the Herzberg bands to the atomic oxygen peak density.

  19. Characteristics of methane and nitrous oxide emissions from the wastewater treatment plant.

    PubMed

    Hwang, Kum-Lok; Bang, Cheon-Hee; Zoh, Kyung-Duk

    2016-08-01

    The nitrous oxide (N2O) and methane (CH4) emissions were measured from a municipal wastewater treatment plant (WWTP) using a flux chamber to determine the emission factors. The WWTP treats sewage using both the activated-sludge treatment and anaerobic/anoxic/aerobic (A(2)O) methods. Measurements were performed in the first settling, aeration, and secondary settling basins, as well as in the sludge thickener, sludge digestion tank, and A(2)O basins. The total emission factors of N2O and CH4 from the activated-sludge treatment were 1.256gN2O/kg total nitrogen (TN) and 3.734gCH4/kg biochemical oxygen demand (BOD5), respectively. Those of the advanced treatment (A(2)O) were 1.605gN2O/kg TN and 4.022gCH4/kgBOD5, respectively. These values are applicable as basic data to estimate greenhouse gas emissions. PMID:27237575

  20. Mote cyclone robber system particulate emission factors for cotton gins: Particle size distribution characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report is part of a project to characterize cotton gin emissions from the standpoint of total particulate stack sampling and particle size analyses. In 2013, the U.S. Environmental Protection Agency (EPA) published a more stringent standard for particulate matter with nominal diameter less than...